Automatic merge from submit-queue (batch tested with PRs 65882, 65896, 65755, 60549, 65927). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Add script to verify generated files
**What this PR does / why we need it**:
This is probably *really* heavy handed fix to this, but it will catch issues in presubmit.
Basically, takes a copy of the repo, clears out anything that is ignored from the git tree, runs `make generated_files`, and looks for a git diff. If there is one, error. Anything that is properly gitignored won't cause a diff, but anything that is *supposed* to be checked in, but is different, this will catch.
**Special notes for your reviewer**:
I'm open to more elegant answers, but this will at least stop it from happening for now.
**Release note**:
```release-note
NONE
```