add typing annotations for a few torch.utils.* modules (#43806)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/43431. Depends on [gh-43862](https://github.com/pytorch/pytorch/pull/43862) (EDIT: now merged)
Modules:
- torch.utils.mkldnn
- torch.utils.mobile_optimizer
- torch.utils.bundled_inputs
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43806
Reviewed By: gmagogsfm
Differential Revision: D23635151
Pulled By: SplitInfinity
fbshipit-source-id: a85b75a7927dde6cc55bcb361f8ff601ffb0b2a1
