[Perl/perl5] 0b60db: locale.c: Avoid some locale switching

[Karl Williamson via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 0b60dbbe529b372662069aaadf3dfcf18f85c1cc
      
https://github.com/Perl/perl5/commit/0b60dbbe529b372662069aaadf3dfcf18f85c1cc
  Author: Karl Williamson <k...@cpan.org>
  Date:   2023-12-20 (Wed, 20 Dec 2023)

  Changed paths:
    M locale.c

  Log Message:
  -----------
  locale.c: Avoid some locale switching

In our emulation of nl_langinfo(), prior to this commit, we always
toggled the locales of two categories to the necessary ones.  But it
turns out that some paths through the code don't require this toggling.
This commit narrows the scope of the toggling to just those cases that
need it.