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.

Lib/test/support/testresult.py

@@ -8,6 +8,7 @@ import sys
 import time
 import traceback
 import unittest
+from test import support
 
 class RegressionTestResult(unittest.TextTestResult):
     USE_XML = False
@@ -112,6 +113,8 @@ class RegressionTestResult(unittest.TextTestResult):
     def addFailure(self, test, err):
         self._add_result(test, True, failure=self.__makeErrorDict(*err))
         super().addFailure(test, err)
+        if support.failfast:
+            self.stop()
 
     def addSkip(self, test, reason):
         self._add_result(test, skipped=reason)