pytorch

725d6cd8 - Extract common classes and functions from test_c10d to common_distributed (#23660)

Extract common classes and functions from test_c10d to common_distributed (#23660) Summary: MultiProcessTestCase will be useful for both c10d and rpc tests. So, this diff extracts that class and some common decorators to a separate file. Pull Request resolved: https://github.com/pytorch/pytorch/pull/23660 Reviewed By: pietern Differential Revision: D16602865 Pulled By: mrshenli fbshipit-source-id: 85ad47dfb8ba187b7debeb3edeea5df08ef690c7