Move NCCL installation for xenial-cuda10.1 to Docker image instead of for every job (#46476)
Summary:
Instead of installing NCCL for every build and test job with environment `*-xenial-cuda10.1-*`, install NCCL into the Docker image. This would save time and remove duplication in our scripts.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46476
Reviewed By: ailzhang
Differential Revision: D24369397
Pulled By: janeyx99
fbshipit-source-id: c107aac9845024d2621eb967ca83c5fc8127a950
