* bpo-33718: regrtest: use format_duration() to display failed tests (GH-7686)
* Enhance also format_duration(): work on integers and rounds towards
+infinity (math.ceil).
* Write unit tests on format_duration()
(cherry picked from commit 4ffe9c2b25)
* bpo-33873: regrtest: Add warning on -R 1:3 (GH-7736)
regrtest: Add warning when using less than 3 warmup runs like -R 1:3.
(cherry picked from commit cac4fef886)
* bpo-33873: Fix bug in `runtest.py` and add checks for invalid `-R` parameters (GH-7735)
Fix bug in `Lib/test/libregrtest/runtest.py` that makes running tests an extra time than the specified number of runs.
Add check for invalid --huntrleaks/-R parameters.
(cherry picked from commit 58ed7307ea)
(cherry picked from commit d1f9481b7a)
