Actually run backward criterion tests. (#44030)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44030
This looks to have been a mistake from https://github.com/pytorch/pytorch/pull/9287.
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D23476274
Pulled By: gchanan
fbshipit-source-id: 81ed9d0c9a40d49153fc97cd69fdcd469bec0c73
