gh-132719: Skip multiprocessing test if missing ctypes (#132842)

Skip test_lock_locked_2processes() if multiprocessing.sharedctypes is
missing (need ctypes).

Author: vstinner

Lib/test/_test_multiprocessing.py

@@ -1516,6 +1516,7 @@ def _test_lock_locked_2processes(cls, lock, event, res):
         res.value = lock.locked()
         event.set()
 
+    @unittest.skipUnless(HAS_SHAREDCTYPES, 'needs sharedctypes')
     def test_lock_locked_2processes(self):
         if self.TYPE != 'processes':
             self.skipTest('test not appropriate for {}'.format(self.TYPE))