sv.c: Add comment
lib/locale.t: Improve test names; add some names
lib/locale.t: Add some tests
lib/locale.t: Add tests, fix test names

It is unfortunate that tests are in two places in this file.  The reason
is to avoid doing eval's (to avoid any perturbations that might cause)
but be under the scope of two different locale forms.  This adds text to
remind maintainers that they should create copies when adding tests, and
includes the new tests that have previously been added to one place but
not the other, and includes the new improved test names.
lib/utf8.pm: wrap code examples in pod with C<>
lib/utf8.pm: Document unicode_to_native() and inverse
PATCH: [perl #120386]: av_len documentation

I think I have incorporated everybody's concerns in this patch.
utfebcdic.h: Add comments
perlebcdic: Clean-up

There are much simpler ways to do some things than were given.  This
also makes some clarifications, and removes obsolete text, shortens some
too long verbatim lines.