[PyTorch Tests] Split out skip logic, make changes for plugins (#67256)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67256
To change what tests can be run in various cases, the check logic should be moved to functions and variables that can be changed.
One challenge here is that decorators don't have dynamic functionality. If something is read in when imported and then changed afterwards, it will not actually change. This means we need to separate out the variables that need to be changed for our use case.
Those are put into common_distributed.py and can be changed before importing the distributed_test.py code.
The use case is to add new backends to the tests and split it into tests that can be ran on demand as a separate instance. To do so, you would change DistTestSkipCases after importing it into a launcher or a setup script and then load distributed_test.
Test Plan: Check the signals
Reviewed By: mrshenli
Differential Revision: D31906947
fbshipit-source-id: 45e3258c55f4dc34e12a468bed65280f4c25748f
