Rename torchtest.test_all_device_types to torchtest.for_all_device_types (#24337)
Summary:
Rename decorator to `for_all_device_types` as `test_` prefixed name recognized as test in some environments.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24337
Differential Revision: D16806807
Pulled By: VitalyFedyunin
fbshipit-source-id: 3132366046e183329ba5838a4bc29441fdb5bd4e
