Back out "Revert D31005792: [NCCL] Init dummy NCCL comms in constructor" (#65883)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65883
Original commit changeset: d8e962b8aab6
ghstack-source-id: 139836954
Test Plan: ci
Reviewed By: zhaojuanmao
Differential Revision: D31299350
fbshipit-source-id: 9ad5c8fa17f7038ba579cb1eda6d9271ac07a130
