[BE] replace unittest.main with run_tests (#50451)
Summary:
fix https://github.com/pytorch/pytorch/issues/50448.
This replaces all `test/*.py` files with run_tests(). This PR does not address test files in the subdirectories because they seems unrelated.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50451
Reviewed By: janeyx99
Differential Revision: D25899924
Pulled By: walterddr
fbshipit-source-id: f7c861f0096624b2791ad6ef6a16b1c4895cce71
Author
Rong Rong (AI Infra)
