[Wav2vec2 + LM Test] Improve wav2vec2 with lm tests and make torch version dependent for now
Trying to correct potentially flaky test: 
```
tests/models/wav2vec2_with_lm/test_processor_wav2vec2_with_lm.py::Wav2Vec2ProcessorWithLMTest::test_word_time_stamp_integration
```
The test actually always passed for me locally.

I've now changed list to tensor as list comparison with float numbers seems brittle. @ydshieh - just to better understand, is this test consistently failing or was it flaky?
It fails consistently since PT 1.12.<|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>Note after some more debugging the reason seems to be in `datasets`. E.g. this part of the test:

```python
ds = load_dataset("common_voice", "en", split="train", streaming=True)
ds = ds.cast_column("audio", datasets.Audio(sampling_rate=16_000))
ds_iter = iter(ds)
sample = next(ds_iter)
print(sample["audio"]["array"])
```

yields different results between `torchaudio=0.11.0` and `torchaudio=0.12.1`. Opening an issue in Datasets.<|||||>@ydshieh good for a second review