TST: tighten check_categorical=False tests
This removes all check_categorical=False usages except for a) those in tests/util and b) a skipped json test test_latin_encoding (cc @WillAyd is that likely to be enabled in the foreseeable future?)
> skipped json test test_latin_encoding (cc @WillAyd is that likely to be enabled in the foreseeable future?)

I'm not familiar with that test / background but would think not. Looks like its part of #13774 will comment there @jorisvandenbossche any objection to removing check_categorical kwarg from assert_series_equal now that we no longer use it? > @jorisvandenbossche any objection to removing check_categorical kwarg from assert_series_equal now that we no longer use it?

Yes, it's a public keyword, so needs to be deprecated first if we want to remove it. 