Adding support for `fp16` for asr pipeline. (#20864)
* Supporting `fp16` for asr pipeline
* Adding test.
* Style.
* Oops.
* Flake8 update ?
* Fixing flake8 ?
* Revert "Flake8 update ?"
This reverts commit 0b917fcb520e5f34d1933d9d37d8f32b64553048.
* Style (acctidentally deleted flake8 F401.)
* Move to a bigger test (no small whisper model, and s2t doesn't seem to
accept torch_dtype=fp16).
Also we need to use a GPU to actually compute on fp16.
* Using BatchFeature capability.
