Add a OperatorHandle argument to boxed kernels (#29201)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29201
This is required for boxed backend fallback kernels (e.g. lazy, AMP) because they need to know which op was actually called.
ghstack-source-id: 94481313
Test Plan: I will add unit tests in a diff stacked on top
Differential Revision: D18282746
fbshipit-source-id: 339a1bbabd6aff31a587b98f095c75104dfc6f99
