BUG: tz_localize needs to invalidate freq
- [x] closes #30511
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Identified when trying to add `freq` check to `assert_index_equal` for DatetimeIndex and TimedeltaIndex.