benchmark

38b23e6b - Add get_optimizer and set_optimizer to BenchmarkModel API (#1457)

Add get_optimizer and set_optimizer to BenchmarkModel API (#1457) Summary: non ghstack version of https://github.com/pytorch/benchmark/issues/1452 Pull Request resolved: https://github.com/pytorch/benchmark/pull/1457 Reviewed By: xuzhao9 Differential Revision: D43859895 Pulled By: janeyx99 fbshipit-source-id: e180c66cf392c06dfa5423b1ac9f2b116a49ef6d