TST: check whether printing an IntervalIndex works (GH32553)
- [x] closes #32553
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry (not applicable)

I just added a test that checks whether print succeeds, would we also want to check the exact output of the `str` function on an `IntervalIndex`?
