[BE] add test selector to test_testing (#55931)
Summary:
This is a reflection of recent failures in https://github.com/pytorch/pytorch/issues/55753 and https://github.com/pytorch/pytorch/issues/55522.
We are lacking a test to safeguard these test env var.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55931
Test Plan:
1. CI
2. Run locally using `python test/test_testing.py -k test_filtering_env_var -v`
- gives failure on 2ca45cb9e8 and d0cd16899f
- passes on 159e1100bf and current master
Reviewed By: jbschlosser
Differential Revision: D27747537
Pulled By: walterddr
fbshipit-source-id: c88e1c818199c7838866037d702d4012cacf510e
Author
Rong Rong (AI Infra)