promote torch.testing to stable (#73348)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/73348
Test Plan: Imported from OSS
Reviewed By: mrshenli
Differential Revision: D34457727
Pulled By: mruberry
fbshipit-source-id: 2cc812b643e0d1e753bead2751ee79b3f03fde20
(cherry picked from commit bcdaca1a019a679b8b274e2fb5f19bfd08874ce9)
