Do not rebase select nighly builds on top of master (#46038)
Summary:
Prevents the following nightly failures from happening:
https://app.circleci.com/pipelines/github/pytorch/pytorch/224752/workflows/3a01ccc2-0215-4e95-9222-bbb4f9309201/jobs/8084912
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46038
Reviewed By: seemethere
Differential Revision: D24195706
Pulled By: malfet
fbshipit-source-id: d53da554bc43841ab6573188f9465c691c601eb3
