TST: More old issues
- [x] closes #19354
- [x] closes #19517
- [x] closes #20414
- [x] closes #20420
- [x] closes #20520
- [x] closes #20734
- [x] closes #20951
- [x] closes #21651
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them

thanks @mroeschke 