JIT: guard DifferentiableGraph node (#49433)
Summary:
This adds guarding for DifferentiableGraph nodes in order to not depend on
Also bailing out on required gradients for the CUDA fuser.
Fixes https://github.com/pytorch/pytorch/issues/49299
I still need to look into a handful of failing tests, but maybe it can be a discussion basis.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49433
Reviewed By: ngimel
Differential Revision: D25681374
Pulled By: Krovatkin
fbshipit-source-id: 8e7be53a335c845560436c0cceeb5e154c9cf296
