pytorch

30648985 - Revert D22108899: Ensure NCCL_BLOCKING_WAIT=1 works for dist.barrier()

Revert D22108899: Ensure NCCL_BLOCKING_WAIT=1 works for dist.barrier() Test Plan: revert-hammer Differential Revision: D22108899 Original commit changeset: 6b109ef9357e fbshipit-source-id: 41ca36091a7d4d5e94143835809560362fb14fcd