detect mocked module on saving pass (#70641)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70641
Raises a not implemented error if we attempt to pickle an object which uses a mocked module. Now we no longer have to load the object to get this check, and instead happens right on the saving path.
Review History is on https://github.com/pytorch/pytorch/pull/69793 PR was moved to a different branch due to original branch getting corrupted.
Test Plan: Imported from OSS
Reviewed By: suo
Differential Revision: D33414365
Pulled By: PaliC
fbshipit-source-id: 6d72ddb05c47a3d060e9622ec0b6e5cd6c6c71c8
