Enable torch.utils typechecks (#42960)
Summary:
Fix typos in torch.utils/_benchmark/README.md
Add empty __init__.py to examples folder to make example invocations from README.md correct
Fixed uniform distribution logic generation when mixval and maxval are None
Fixes https://github.com/pytorch/pytorch/issues/42984
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42960
Reviewed By: seemethere
Differential Revision: D23095399
Pulled By: malfet
fbshipit-source-id: 0546ce7299b157d9a1f8634340024b10c4b7e7de
