Fix integration tests for `TFWav2Vec2` and `TFHubert`
**Issue**
Errors for integration tests on `TFWav2Vec2` and `TFHubert`
```
E           ValueError: When setting ``truncation=True``, make sure that ``max_length`` is defined and ``padding='max_length'
```
CI logs: https://github.com/huggingface/transformers/runs/3539314355?check_suite_focus=true

**Solution**
Remove `truncation=True` from feature extractors since the logic changed recently https://github.com/huggingface/transformers/pull/12804/
Also some other small fixes because the tests now reach those lines :slightly_smiling_face: 