text: Title: BUG: xorbits.numpy.tril cannot handle 1-d array input
  Body: ### Describe the bug
  xorbits.numpy.tril raises exception when the given input is a 1-d array.
  
  ### To Reproduce
  ```python
  np.tril(np.ones(5))
  ```
  
  ### Expected behavior
  Output:
  ```python
  array([[1., 0., 0., 0., 0.],
         [1., 1., 0., 0., 0.],
         [1., 1., 1., 0., 0.],
         [1., 1., 1., 1., 0.],
         [1., 1., 1., 1., 1.]])
  ```
  
  ### Additional context
  ```
  File ~/Documents/miniconda3/envs/prod/lib/python3.9/site-packages/xorbits/_mars/tensor/datasource/tri.py:58, in TensorTri.tile(cls, op)
       56 out_chunks = []
       57 for out_idx in itertools.product(*[range(len(s)) for s in nsplits]):
  ---> 58     i, j = out_idx[-2:]
       59     ld_pos = cum_size[-2][i] - 1, cum_size[-1][j] - nsplits[-1][j]
       60     ru_pos = cum_size[-2][i] - nsplits[-2][i], cum_size[-1][j] - 1
  
  ValueError: not enough values to unpack (expected 2, got 1)
  ```