Don't use NonVariableTypeMode in custom ops (#37355)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37355
Potentially fixes https://github.com/pytorch/pytorch/issues/37306
ghstack-source-id: 103073537
Test Plan: waitforsandcastle
Differential Revision: D21261946
fbshipit-source-id: 454652b528dcf942bec5438f89201822de40bbf0
