add sharding option to test framework (#45988)
Summary:
Adding a sharding node to our python CONFIG_TREE
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45988
Reviewed By: mruberry
Differential Revision: D24200636
Pulled By: janeyx99
fbshipit-source-id: 08c8c4cf98bbd4980fe6082ae6caa64fbc2ca792
