gh-91904: Fix setting envvar PYTHONREGRTEST_UNICODE_GUARD (GH-91905)

It always failed on non-UTF-8 locale and prevented running regrtests.
(cherry picked from commit 54d068adfbf2b822bcbf90dac9b3f6684cec0f99)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Miss Islington (bot) committed 4y ago

971343eb569a3418aa9a0bad9b638cccf1470ef8

Parent: dc31334

Committed by GitHub <noreply@github.com> on 4/25/2022, 3:03:47 PM