clean up D13579188 (#15759)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/15759
Some flags have too long names. And some other few minor clean ups.
Reviewed By: jianyuh
Differential Revision: D13587353
fbshipit-source-id: f8aee7f167505644f5d8f80fe2eed70201ef1e54
