Release the GIL before invokeOperator (#42341)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/41865
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42341
Reviewed By: ezyang
Differential Revision: D22928622
Pulled By: wconstab
fbshipit-source-id: 8fa41277c9465f816342db6ec0e6cd4b30095c5c
