chore: update closed conn tests

Author: kgala2

google/cloud/sql/connector/connector.py

@@ -467,7 +467,6 @@ def close(self) -> None:
                 self._loop.call_soon_threadsafe(self._loop.stop)
             # wait for thread to finish closing (i.e. loop to stop)
             self._thread.join()
-        self._closed = True
 
     async def close_async(self) -> None:
         """Helper function to cancel the cache's tasks

tests/unit/test_connector.py

@@ -501,7 +501,7 @@ def test_connect_closed_connector(
     with Connector(credentials=fake_credentials) as connector:
         connector._client = fake_client
         connector.close()
-        time.sleep(0.1)
+        time.sleep(3.1)
         with pytest.raises(RuntimeError) as exc_info:
             connector.connect(
                 "test-project:test-region:test-instance",