text: Title: [BUG] Series.drop_duplicates raised a `TypeError`
  Body: <!--
  Thank you for your contribution!
  
  Please review https://github.com/mars-project/mars/blob/master/CONTRIBUTING.rst before opening an issue.
  -->
  
  **Describe the bug**
  
  Failed to execute `Series.drop_duplicates`.
  
  ``` Python
  In [75]: a = md.DataFrame(np.random.rand(10, 2), columns=['a', 'b'], chunk_size=2)                  
  
  In [76]: a['a'].drop_duplicates().execute()                                                         
    0%|                                                                       | 0/100 [00:00<?, ?it/s]Failed to run subtask l8o2G1V5iJMZVFK7USec2C0k on band numa-0
  Traceback (most recent call last):
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 263, in internal_run_subtask
      subtask, band_name, subtask_api, batch_quota_req)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 340, in _retry_run_subtask
      return await _retry_run(subtask, subtask_info, _run_subtask_once)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 83, in _retry_run
      raise ex
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 67, in _retry_run
      return await target_async_func(*args)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 301, in _run_subtask_once
      return await asyncio.shield(aiotask)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/api.py", line 59, in run_subtask_in_slot
      return await ref.run_subtask(subtask)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 154, in send
      return self._process_result_message(result)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 59, in _process_result_message
      raise message.error.with_traceback(message.traceback)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/pool.py", line 496, in send
      result = await future
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/api.py", line 118, in __on_receive__
      return await super().__on_receive__(message)
    File "mars/oscar/core.pyx", line 351, in __on_receive__
      raise ex
    File "mars/oscar/core.pyx", line 345, in mars.oscar.core._BaseActor.__on_receive__
      return await self._handle_actor_result(result)
    File "mars/oscar/core.pyx", line 250, in _handle_actor_result
      result = list(dones)[0].result()
    File "mars/oscar/core.pyx", line 273, in mars.oscar.core._BaseActor._run_actor_async_generator
      with debug_async_timeout('actor_lock_timeout',
    File "mars/oscar/core.pyx", line 275, in mars.oscar.core._BaseActor._run_actor_async_generator
      async with self._lock:
    File "mars/oscar/core.pyx", line 279, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await gen.athrow(*res)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/runner.py", line 104, in run_subtask
      result = yield self._running_processor.run(subtask)
    File "mars/oscar/core.pyx", line 284, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await self._handle_actor_result(res)
    File "mars/oscar/core.pyx", line 219, in _handle_actor_result
      result = await result
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 154, in send
      return self._process_result_message(result)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 59, in _process_result_message
      raise message.error.with_traceback(message.traceback)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/pool.py", line 496, in send
      result = await future
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/api.py", line 118, in __on_receive__
      return await super().__on_receive__(message)
    File "mars/oscar/core.pyx", line 351, in __on_receive__
      raise ex
    File "mars/oscar/core.pyx", line 345, in mars.oscar.core._BaseActor.__on_receive__
      return await self._handle_actor_result(result)
    File "mars/oscar/core.pyx", line 250, in _handle_actor_result
      result = list(dones)[0].result()
    File "mars/oscar/core.pyx", line 273, in mars.oscar.core._BaseActor._run_actor_async_generator
      with debug_async_timeout('actor_lock_timeout',
    File "mars/oscar/core.pyx", line 275, in mars.oscar.core._BaseActor._run_actor_async_generator
      async with self._lock:
    File "mars/oscar/core.pyx", line 279, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await gen.athrow(*res)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/processor.py", line 482, in run
      result = yield self._running_aio_task
    File "mars/oscar/core.pyx", line 284, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await self._handle_actor_result(res)
    File "mars/oscar/core.pyx", line 219, in _handle_actor_result
      result = await result
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/processor.py", line 374, in run
      stored_keys, store_sizes, memory_sizes, data_key_to_object_id = await self._store_data(chunk_graph)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/processor.py", line 248, in _store_data
      result_chunk.params = result_chunk.get_params_from_data(result_data)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/dataframe/core.py", line 1443, in get_params_from_data
      value=data.dtypes)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/dataframe/core.py", line 355, in __init__
      super().__init__(_key=key, _value=value, **kw)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/serialization/serializables/core.py", line 67, in __init__
      object.__setattr__(self, key, val)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/serialization/serializables/field.py", line 106, in __set__
      raise type(e)(f'Failed to set `{self._attr_name}`: {str(e)}')
  TypeError: Failed to set `_value`: value needs to be instance of (<class 'pandas.core.series.Series'>,), got <class 'numpy.dtype[float64]'>
  Subtask l8o2G1V5iJMZVFK7USec2C0k errored
  Traceback (most recent call last):
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 263, in internal_run_subtask
      subtask, band_name, subtask_api, batch_quota_req)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 340, in _retry_run_subtask
      return await _retry_run(subtask, subtask_info, _run_subtask_once)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 83, in _retry_run
      raise ex
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 67, in _retry_run
      return await target_async_func(*args)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/scheduling/worker/execution.py", line 301, in _run_subtask_once
      return await asyncio.shield(aiotask)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/api.py", line 59, in run_subtask_in_slot
      return await ref.run_subtask(subtask)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 154, in send
      return self._process_result_message(result)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 59, in _process_result_message
      raise message.error.with_traceback(message.traceback)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/pool.py", line 496, in send
      result = await future
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/api.py", line 118, in __on_receive__
      return await super().__on_receive__(message)
    File "mars/oscar/core.pyx", line 351, in __on_receive__
      raise ex
    File "mars/oscar/core.pyx", line 345, in mars.oscar.core._BaseActor.__on_receive__
      return await self._handle_actor_result(result)
    File "mars/oscar/core.pyx", line 250, in _handle_actor_result
      result = list(dones)[0].result()
    File "mars/oscar/core.pyx", line 273, in mars.oscar.core._BaseActor._run_actor_async_generator
      with debug_async_timeout('actor_lock_timeout',
    File "mars/oscar/core.pyx", line 275, in mars.oscar.core._BaseActor._run_actor_async_generator
      async with self._lock:
    File "mars/oscar/core.pyx", line 279, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await gen.athrow(*res)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/runner.py", line 104, in run_subtask
      result = yield self._running_processor.run(subtask)
    File "mars/oscar/core.pyx", line 284, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await self._handle_actor_result(res)
    File "mars/oscar/core.pyx", line 219, in _handle_actor_result
      result = await result
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 154, in send
      return self._process_result_message(result)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/context.py", line 59, in _process_result_message
      raise message.error.with_traceback(message.traceback)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/backends/pool.py", line 496, in send
      result = await future
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/oscar/api.py", line 118, in __on_receive__
      return await super().__on_receive__(message)
    File "mars/oscar/core.pyx", line 351, in __on_receive__
      raise ex
    File "mars/oscar/core.pyx", line 345, in mars.oscar.core._BaseActor.__on_receive__
      return await self._handle_actor_result(result)
    File "mars/oscar/core.pyx", line 250, in _handle_actor_result
      result = list(dones)[0].result()
    File "mars/oscar/core.pyx", line 273, in mars.oscar.core._BaseActor._run_actor_async_generator
      with debug_async_timeout('actor_lock_timeout',
    File "mars/oscar/core.pyx", line 275, in mars.oscar.core._BaseActor._run_actor_async_generator
      async with self._lock:
    File "mars/oscar/core.pyx", line 279, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await gen.athrow(*res)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/processor.py", line 482, in run
      result = yield self._running_aio_task
    File "mars/oscar/core.pyx", line 284, in mars.oscar.core._BaseActor._run_actor_async_generator
      res = await self._handle_actor_result(res)
    File "mars/oscar/core.pyx", line 219, in _handle_actor_result
      result = await result
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/processor.py", line 374, in run
      stored_keys, store_sizes, memory_sizes, data_key_to_object_id = await self._store_data(chunk_graph)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/services/subtask/worker/processor.py", line 248, in _store_data
      result_chunk.params = result_chunk.get_params_from_data(result_data)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/dataframe/core.py", line 1443, in get_params_from_data
      value=data.dtypes)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/dataframe/core.py", line 355, in __init__
      super().__init__(_key=key, _value=value, **kw)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/serialization/serializables/core.py", line 67, in __init__
      object.__setattr__(self, key, val)
    File "/Users/hekaisheng/Documents/mars_dev/mars/mars/serialization/serializables/field.py", line 106, in __set__
      raise type(e)(f'Failed to set `{self._attr_name}`: {str(e)}')
  TypeError: Failed to set `_value`: value needs to be instance of (<class 'pandas.core.series.Series'>,), got <class 'numpy.dtype[float64]'>
  ```
  
  