libc/locale: Fix type breakage in __collate_range_cmp().

When collation support was brought in, the second and third
arguments in __collate_range_cmp() were changed from int to
wchar_t, breaking the ABI. Change them to a "char" type which
makes more sense and keeps the ABI compatible.

Also introduce __wcollate_range_cmp() which does work with wide
characters. This function is used only internally in libc so
we don't export it. Use the new function in glob(3), fnmatch(3),
and regexec(3).

PR: 179721
Suggested by: ache. jilles
MFC after: 3 weeks (perhaps partial only)