Enable torch.backends.cuda typechecking in CI (#44916)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/44916
Reviewed By: walterddr
Differential Revision: D23769844
Pulled By: malfet
fbshipit-source-id: 3be3616fba9e2f9c6d89cc71d5f0d24ffcc45cf2
