[WIP] Add a `_flush_compilation_cache` for testing (#52001)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/52001
Reviewed By: eellison
Differential Revision: D26371876
Pulled By: Krovatkin
fbshipit-source-id: db773d7124916bad31e80bdd7bb9b4170060977b
