[distributed] add processgroup options as argument (#53663)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53663
This add the processgroup option as an optional argument to new_group
and init_processgroup, this allows user to pass in a initialized
processgroup option for gloo and nccl.
Test Plan: Imported from OSS
Reviewed By: rohan-varma
Differential Revision: D26968857
Pulled By: wanchaol
fbshipit-source-id: 2ff73a009120b85e83ecde7c69956b731902abc2
