Add test jobs on CPU agents for CUDA builds on Windows (#37904)
Summary:
Targets https://github.com/pytorch/pytorch/pull/37811#issuecomment-624367089.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37904
Differential Revision: D21484360
Pulled By: seemethere
fbshipit-source-id: b25cbf35b8432a587bce86815c97ff444cab255c
