Split `test_testing.py::TestAsserts` for multiple devices (#56365)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56365
Follow-up to https://github.com/pytorch/pytorch/pull/54784#discussion_r614156172. Instead of having one large testcase where most methods are decorated with `onlyCPU`, this factors out all tests that actually need another device into a separate test case.
Test Plan: Imported from OSS
Reviewed By: walterddr, albanD
Differential Revision: D28247529
Pulled By: mruberry
fbshipit-source-id: 946e7694b70e736941565f29b5dd459ed7fbca4e
