[3.12] pythongh-105699: Re-enable the Multiple-Interpreters Stress Te…

…sts (pythongh-107572) (python#107783)

We had disabled them due to crashes they exposed, which have since been fixed.
(cherry picked from commit f9e3ff1)

Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
Co-authored-by: Łukasz Langa <lukasz@langa.pl>
Co-authored-by: T. Wouters <thomas@python.org>

Lib/test/test_interpreters.py

@@ -464,7 +464,6 @@ def test_bytes_for_script(self):
     # test_xxsubinterpreters covers the remaining Interpreter.run() behavior.
 
 
-@unittest.skip('these are crashing, likely just due just to _xxsubinterpreters (see gh-105699)')
 class StressTests(TestBase):
 
     # In these tests we generally want a lot of interpreters,