<regex>: Implement collating ranges

[muellerj2]

Resolves #5204. Follow-up to #5164 and #5209.

When compiled under /MD or /MDd, the new test cases specific to collating ranges are skipped:

• if compiled with /Zc:wchar_t- because the test will fail due to <locale>: std::collate<wchar_t> does not respect collation order when compiled with /MD(d) /Zc:wchar_t- #5236.
• if there is a mismatch with _ITERATOR_DEBUG_LEVEL because the stack will be corrupted when std::collate<wchar_t>::do_transform() is called in the linked DLL.

Drive-by changes:

• Mark _Parser::_Error() as [[noreturn]].
• In _Matcher::_Skip() and _Matcher::_Do_class(), _STD qualify calls to some free functions and clean up the control flow that translates the current character and converts it to an unsigned value.

[StephanTLavavej]

Thanks! This makes sense and looks good to me. The comprehensive test coverage is excellent. 😻

I pushed a trivial merge with main followed by a bunch of nitpicks. The most significant changes were to regex_with_locale_should_throw(), to actually use syntax and to properly record failure when an exception is thrown with an unexpected code.

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

Thanks for sorting out this bug! 😹 🐞 🪄