Use maximum of tolerances in case of mismatching dtypes (#60636)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60636
See https://github.com/pytorch/pytorch/pull/58981#issuecomment-866654600.
Test Plan: Imported from OSS
Reviewed By: ngimel
Differential Revision: D29556352
Pulled By: mruberry
fbshipit-source-id: 36e97e0f338df5d17a94af078f172c668ef51ecb
