Make sure to reap worker threads and processes at the end of test_concurrent_futures

Lib/test/test_concurrent_futures.py

@@ -623,7 +623,9 @@ class FutureTests(unittest.TestCase):
 
         self.assertTrue(isinstance(f1.exception(timeout=5), IOError))
 
+@test.support.reap_threads
 def test_main():
+    try:
         test.support.run_unittest(ProcessPoolExecutorTest,
                                   ThreadPoolExecutorTest,
                                   ProcessPoolWaitTests,
@@ -633,6 +635,8 @@ def test_main():
                                   FutureTests,
                                   ProcessPoolShutdownTest,
                                   ThreadPoolShutdownTest)
+    finally:
+        test.support.reap_children()
 
 if __name__ == "__main__":
     test_main()