[Gradient Compression] Refactor default_hooks.py and powerSGD_hook.py by creating a util function that make a vanilla allreduce future (#51094)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51094
Address https://github.com/pytorch/pytorch/pull/50973#discussion_r564229818
Original PR issue: Investigate Applying PowerSGD to Communication Hook for Gradient Compression #47202
ghstack-source-id: 120619680
Test Plan:
buck test mode/dev-nosan caffe2/test/distributed:c10d -- test_powerSGD_ddp_comm_hook_nccl
buck test mode/dev-nosan caffe2/test/distributed:c10d -- test_default_ddp_comm_hooks_nccl
Reviewed By: rohan-varma
Differential Revision: D26070147
fbshipit-source-id: 8c9339f1511e8f24cc906b9411cfe4850a5a6d81
