WIP: TST: split up tests/plotting/test_frame.py into subdir & modules #34769
Moved `tests/plotting/test_frame.py` to `tests/plotting/frame/test_frame.py`.

Worked towards #34769 but not closing it as this has not split the test suite.

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

/azp run <samp>
Azure Pipelines successfully started running 1 pipeline(s).<br>

</samp> can you merge master and ping on green. hi @jreback I have merged master and all checks are green now sorry can u merge master again and ping on green 

also remove WIP from title @iahsanujunda can you fix the merge conflict? GH is showing me an empty diff.  is this active? This pull request is stale because it has been open for thirty days with no activity. Please update or respond to this comment if you're still interested in working on this. Can I continue working on this branch?
Or is it better to create a new request? @Mikhaylov-yv pls create a new PR