change test_name to be globally unique value across tests (#21206)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21206
This diff change the default test_name to be a globally unique value across tests. With that, users can list all the tests and choose to run a specific test.
Reviewed By: zheng-xq
Differential Revision: D15543508
fbshipit-source-id: 0814ef6a60d41637fed5245e30c282497cf21bb8
