What would you like to be added?

Backport all the failpoint comments from main branch to release-3.4 and release-3.5.
For example compactBeforeSetFinishedCompact from #17780

TODO:
Find all comments like // gofail: var compactBeforeSetFinishedCompact struct{} and backport them to old releases.

Why is this needed?

This will allow running #17815 on old releases and allow robustness test to use them.