TST: add test cases for reset_index method
- [x] closes #17067
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

the fix appears to work but it breaks previous assert_frame_equal that assumes index.name == None after reset_index() call. 

The question remains that is the issue #17067 actually a bug and does it require a fix at all? user can pretty much do `series.index.name = 'new name'` to handle this problem.