bpo-36253: Remove use after free reference in ctypes test suite (GH-12257)

Lib/ctypes/test/test_stringptr.py

@@ -70,8 +70,8 @@ class StringPtrTestCase(unittest.TestCase):
         x = r[0], r[1], r[2], r[3], r[4]
         self.assertEqual(x, (b"c", b"d", b"e", b"f", b"\000"))
         del buf
-        # x1 will NOT be the same as x, usually:
-        x1 = r[0], r[1], r[2], r[3], r[4]
+        # Because r is a pointer to memory that is freed after deleting buf,
+        # the pointer is hanging and using it would reference freed memory.
 
 if __name__ == '__main__':
     unittest.main()