test experiment script (#57925)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57925
1. adds test_scripts.py that will run added scripts and verify that there are no errors
2. adds local ddp_nccl_allreduce experiment script
test with command `pytest test_scripts.py`
Test Plan: Imported from OSS
Reviewed By: agolynski
Differential Revision: D28382452
Pulled By: gcramer23
fbshipit-source-id: 21028a990ebfedf1aad6b007a723c02403e8bea8
