Py39 Support - Remove Deprecated Unicode Length Check
- [X] closes #36279
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

huh cythonize error /azp run
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</samp> lgtm. are the CI failures unrelated? we should genreally backport these 3.9 changes if at all possible. @WillAyd can you update Also removed pre per https://github.com/pandas-dev/pandas/issues/36296#issuecomment-693106050 closing as superceded by https://github.com/pandas-dev/pandas/pull/36393