[3.12] gh-108834: Sync libregrtest with the main branch (#108966)

* gh-108834: regrtest reruns failed tests in subprocesses (#108839)

When using --rerun option, regrtest now re-runs failed tests
in verbose mode in fresh worker processes to have more
deterministic behavior. So it can write its final report even
if a test killed a worker progress.

Add --fail-rerun option to regrtest: exit with non-zero exit code
if a test failed pass passed when re-run in verbose mode (in a
fresh process). That's now more useful since tests can pass
when re-run in a fresh worker progress, whereas they failed
when run after other tests when tests are run sequentially.

Rename --verbose2 option (-w) to --rerun. Keep --verbose2 as a
deprecated alias.

Changes:

* Fix and enhance statistics in regrtest summary. Add "(filtered)"
  when --match and/or --ignore options are used.
* Add RunTests class.
* Add TestResult.get_rerun_match_tests() method
* Rewrite code to serialize/deserialize worker arguments as JSON
  using a new WorkerJob class.
* Fix stats when a test is run with --forever --rerun.
* If failed test names cannot be parsed, log a warning and don't
  filter tests.
* test_regrtest.test_rerun_success() now uses a marker file, since
  the test is re-run in a separated process.
* Add tests on normalize_test_name() function.
* Add test_success() and test_skip() tests to test_regrtest.

(cherry picked from commit 31c2945f14)

* gh-108834: regrtest --fail-rerun exits with code 5 (#108896)

When the --fail-rerun option is used and a test fails and then pass,
regrtest now uses exit code 5 ("rerun) instead of 2 ("bad test").

(cherry picked from commit 1170d5a292)

* gh-108416: Mark slow but not CPU bound test methods with requires_resource('walltime') (GH-108480)

(cherry picked from commit 1e0d62793a)

* Manually sync Lib/test/libregrtest/ from main

---------

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

Lib/test/_test_multiprocessing.py

@@ -675,6 +675,7 @@ class _TestProcess(BaseTestCase):
 
         close_queue(q)
 
+    @support.requires_resource('walltime')
     def test_many_processes(self):
         if self.TYPE == 'threads':
             self.skipTest('test not appropriate for {}'.format(self.TYPE))
@@ -4953,6 +4954,7 @@ class TestWait(unittest.TestCase):
     def test_wait_socket_slow(self):
         self.test_wait_socket(True)
 
+    @support.requires_resource('walltime')
     def test_wait_timeout(self):
         from multiprocessing.connection import wait
 
@@ -4981,6 +4983,7 @@ class TestWait(unittest.TestCase):
         sem.release()
         time.sleep(period)
 
+    @support.requires_resource('walltime')
     def test_wait_integer(self):
         from multiprocessing.connection import wait