Fix sharded tensor tests. (#63054)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63054
1) Ensure these tests are skipped in environments without any GPUs.
2) Add the test to run_test.py
ghstack-source-id: 135595698
Test Plan: waitforbuildbot
Reviewed By: wanchaol
Differential Revision: D30239159
fbshipit-source-id: 21b543ba72e8d10182bc77e7ae1fd34fd4096509
