Message 354994 - Python tracker

There are a couple of cases that the C locale coercion tests skip because I don't (or didn't) know what they *should* do:

* https://github.com/python/cpython/blob/24dc2f8c56697f9ee51a4887cf0814b6600c1815/Lib/test/test_c_locale_coercion.py#L262 (skips the "LANG=UTF-8" test)
* https://github.com/python/cpython/blob/24dc2f8c56697f9ee51a4887cf0814b6600c1815/Lib/test/test_c_locale_coercion.py#L37 (only adds "POSIX" to the expected C locale equivalents list on non-Android Linux systems)

With the interpreter explicitly checking for "POSIX" now, at least the latter special case could potentially be removed, with "POSIX" just always being part of the EXPECTED_C_LOCALE_EQUIVALENTS list. (It was only removed because it used to break on FreeBSD and Mac OS X)

I don't think we ever figured out why the "LANG=UTF-8" case didn't work the way we expected, so I suspect where going to need to keep that skip for now.