CLN: Consistent pandas.util.testing imports in pandas/tests/indexing
Part of #29272 

Fyi: All changes are generated from a script posted in the issue.

- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

@SaturnFromTitan can you merge master and push again on this and your other PRs? CI failure unrelated and should have been fixed on master @WillAyd Thanks for letting me know. The PRs are rebased now and all checks passed ✅  Thanks @SaturnFromTitan !