[3.11] [3.12] gh-109413: libregrtest: Backport `.py`-file changes from GH-112558 (GH-112605) (#112607)

[3.12] gh-109413: libregrtest: Backport `.py`-file changes from GH-112558 (GH-112605)
(cherry picked from commit acc62db8af4e472a4922c10b91c60c36c49a5f79)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>