Actually deprecate __torch_function__ as plain methods (#64843)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64843
Fix for https://github.com/pytorch/pytorch/issues/63767
Test Plan: Imported from OSS
Reviewed By: heitorschueroff
Differential Revision: D30991425
Pulled By: albanD
fbshipit-source-id: 1214143b8aea87e6ff406c7fc13096bd15d1a768
