bpo-30110: fix resource leak in test_asyncio.test_events (#1413) (#1584)

diff --git a/Lib/test/test_asyncio/test_events.py b/Lib/test/test_asyncio/test_events.py
index 802763b..492a84a 100644
--- a/Lib/test/test_asyncio/test_events.py
+++ b/Lib/test/test_asyncio/test_events.py
@@ -2194,8 +2194,10 @@
         def test_get_event_loop_new_process(self):
             async def main():
                 pool = concurrent.futures.ProcessPoolExecutor()
-                return await self.loop.run_in_executor(
+                result = await self.loop.run_in_executor(
                     pool, _test_get_event_loop_new_process__sub_proc)
+                pool.shutdown()
+                return result
 
             self.unpatch_get_running_loop()