[BE] Enable PostLocalSGD tests on windows (#63463)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63463
Now that `torch.distributed.optim` gates DistributedOptimizer on RPC availability, local sgd optimizer can be used on windows.
ghstack-source-id: 136437632
Test Plan: Ci
Reviewed By: SciPioneer
Differential Revision: D30358922
fbshipit-source-id: 9b56aebf1075f026637296d338805ad8851c9d40
