Remove unneeded manual unwrap optionals (#16245)
Summary:
Remove calls to torch.jit._unwrap_optional that are no longer needed.
The remaining instances would require control flow logic for exceptions.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16245
Differential Revision: D13804292
Pulled By: eellison
fbshipit-source-id: 08c5cbe4b956519be2333de5cf4e202488aff626
