Add the rest of the `dict` API (#21979)
Summary:
This adds the rest of the `dict.???` methods that were missing
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21979
Pulled By: driazati
Differential Revision: D16023573
fbshipit-source-id: 3ea9bd905090e2a176af654a8ca98c7d965ea679
