Update fallback kernel for Autograd keys. (#44349)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/44349
Test Plan: Imported from OSS
Reviewed By: ezyang
Differential Revision: D23589807
Pulled By: ailzhang
fbshipit-source-id: 0e4b0bf3e07bb4e35cbf1bda22f7b03193eb3dc4
