gh-117657: Skip test when running under TSan (GH-121549)

The ProcessPoolForkserver combined with resource_tracker starts a thread
after forking, which is not supported by TSan.

Also skip test_multiprocessing_fork for the same reason

Lib/test/test_concurrent_futures/test_init.py

@@ -139,6 +139,7 @@ def _test(self, test_class):
     def test_spawn(self):
         self._test(ProcessPoolSpawnFailingInitializerTest)
 
+    @support.skip_if_sanitizer("TSAN doesn't support threads after fork", thread=True)
     def test_forkserver(self):
         self._test(ProcessPoolForkserverFailingInitializerTest)
 

Lib/test/test_multiprocessing_fork/__init__.py

@@ -12,5 +12,8 @@
 if sys.platform == 'darwin':
     raise unittest.SkipTest("test may crash on macOS (bpo-33725)")
 
+if support.check_sanitizer(thread=True):
+    raise unittest.SkipTest("TSAN doesn't support threads after fork")
+
 def load_tests(*args):
     return support.load_package_tests(os.path.dirname(__file__), *args)