Kill the test_torch.py mixin and creates test_scatter_gather_ops (#71691)
Summary:
Per title.
Also annotates test_torch.py with additional cleanup tasks and adds empty sample inputs to elementwise unary and binary OpInfos.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71691
Reviewed By: ngimel
Differential Revision: D33735126
Pulled By: mruberry
fbshipit-source-id: 8cc097a7581a8b620540c95b2a5889c1165ecf23
(cherry picked from commit 5c6a245a3f9ba7c064fc77c8cd4045f903e73cfd)
