Enable step_param for Adam functional optimizer (#62611)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62611
Enables optimizer overlap with backwards in DDP for Adam. Additional optimizers, especially Adagrad will be done in follow up diffs.
1. Implement `step_param` method based on `step` in _FunctionalAdam (perf permitting we can later dedupe `step` to call `step_param`
2. Modify tests to test all current functional optimizers.
ghstack-source-id: 135207143
Test Plan: CI
Reviewed By: SciPioneer
Differential Revision: D29891783
fbshipit-source-id: 321915982afd5cb0a9c2e43d27550f433bff00d1
