Add profiling for backward (#120540)
Summary:
Fixes #ISSUE_NUMBER
X-link: https://github.com/pytorch/pytorch/pull/120540
Approved by: https://github.com/anijain2305
Reviewed By: kit1980
Differential Revision: D54192278
Pulled By: mlazos
fbshipit-source-id: 7e813e112f5ce7b36c1fe62f2018494d495b5dc2
