CLN: Remove long and integer_types from pandas.compat
- [X] xref #25725
- [X] tests added / passed
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Another incremental step in removing Python 2.  Doesn't look like `integer_types` was actually used anywhere.  Otherwise mostly `long` --> `int`, or just removing `long` as the argument was already an `int` in Python 3.
