cleanup torch/nn/functional.py (#23977)
Summary:
Cleanup torch/nn/functional now that JIT:
- Handles multiple returns
- Typechecks exits (exceptions)
- assertions refine types
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23977
Differential Revision: D16697750
Pulled By: eellison
fbshipit-source-id: 1f777d6b9ead1105de50120fffd46d523e1e6797
