gh-89363: Skip threading test_is_alive_after_fork() if ASAN (#109835)

Skip test_is_alive_after_fork() of test_threading if Python is built
with Address Sanitizer (ASAN).

Author: vstinner

Lib/test/_test_multiprocessing.py

@@ -79,7 +79,7 @@
 
 
 if support.check_sanitizer(address=True):
-    # bpo-45200: Skip multiprocessing tests if Python is built with ASAN to
+    # gh-89363: Skip multiprocessing tests if Python is built with ASAN to
     # work around a libasan race condition: dead lock in pthread_create().
     raise unittest.SkipTest("libasan has a pthread_create() dead lock")
 

Lib/test/test_threading.py

@@ -572,6 +572,10 @@ def background_thread(evt):
         self.assertEqual(err, b'')
 
     @support.requires_fork()
+    # gh-89363: Skip multiprocessing tests if Python is built with ASAN to
+    # work around a libasan race condition: dead lock in pthread_create().
+    @support.skip_if_sanitizer("libasan has a pthread_create() dead lock",
+                               address=True)
     def test_is_alive_after_fork(self):
         # Try hard to trigger #18418: is_alive() could sometimes be True on
         # threads that vanished after a fork.