TestCppExtension now removes /tmp/torch_extensions folder so that it can be used by other users in a multi-user environment. (#30095)
Summary:
Previous behaviour: a user runs tests from `TestCppExtension` class so that `/tmp/torch_extensions` is created under her ownership and not removed afterwards,
then the other user's run of the same tests might result in 'Permission denied' exception upon deleting `/tmp/torch_extensions`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30095
Differential Revision: D18770234
Pulled By: ezyang
fbshipit-source-id: 4c6b972e4c4327a94c8b4bf6b0b9998a01c218bb
