lib/locale.t: Change debug output

This combines the output so that all characters are shown in code point
order, with only ASCII alphanumerics displayed literally.  This is
clearer.
lib/locale.t: Display unassigned chars

This adds debug output to list the characters that aren't matched by any
posix class.
lib/locale.t: Add a bunch of tests

I looked through the online standard and added as many conformance tests
as I could think of.
smoke