TST: split up tests/plotting/test_frame.py into subdir & modules #34769
Created instead of #37538

- [x] closes #34769
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

I moved the file to a new directory.
What is the best structure for this folder?

[before_test_ploting_frame](https://gist.github.com/Mikhaylov-yv/999de1451e8ecc836215b30db34ef841)
[after_test_ploting_frame](https://gist.github.com/Mikhaylov-yv/98eca32c21f59cc9e7653cd96d5fabd2)