Conv BN folding data type issue when conv has no bias (#78241)
PR https://github.com/pytorch/pytorch/pull/77042 has fixed the new folding conv-bn data type issue but missing the case when original conv has no bias input.
In this PR:
- Fix the new folding conv-bn's bias data type issue, when conv has no bias but weight as lower precision datatype, the new generated bias data type should be same as conv's weight.
- Move the Autocast JIT Trace UT from `test_jit.py` to `test_jit_autocast.py`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/78241
Approved by: https://github.com/davidberard98
