[Perl/perl5] ae4b4d: locale.c: Improve collation debugging output

[Karl Williamson via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: ae4b4da7c260660769ecdfea5a2989abd9d9dd8a
      
https://github.com/Perl/perl5/commit/ae4b4da7c260660769ecdfea5a2989abd9d9dd8a
  Author: Karl Williamson <k...@cpan.org>
  Date:   2023-07-16 (Sun, 16 Jul 2023)

  Changed paths:
    M locale.c

  Log Message:
  -----------
  locale.c: Improve collation debugging output

This adds a special case for when the buffer is empty