Fix gevent test flakes

src/python/grpcio_tests/commands.py

@@ -121,6 +121,8 @@ class TestGevent(setuptools.Command):
         'testing._client_test.ClientTest.test_infinite_request_stream_real_time',
         # TODO(https://github.com/grpc/grpc/issues/14789) enable this test
         'unit._server_ssl_cert_config_test',
+        # TODO(https://github.com/grpc/grpc/issues/14901) enable this test
+        'protoc_plugin._python_plugin_test.PythonPluginTest',
         # Beta API is unsupported for gevent
         'protoc_plugin.beta_python_plugin_test',
         'unit.beta._beta_features_test',

src/python/grpcio_tests/tests/interop/_insecure_intraop_test.py

@@ -36,6 +36,9 @@ class InsecureIntraopTest(_intraop_test_case.IntraopTestCase,
         self.stub = test_pb2_grpc.TestServiceStub(
             grpc.insecure_channel('localhost:{}'.format(port)))
 
+    def tearDown(self):
+        self.server.stop(None)
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)

src/python/grpcio_tests/tests/interop/_secure_intraop_test.py

@@ -45,6 +45,9 @@ class SecureIntraopTest(_intraop_test_case.IntraopTestCase, unittest.TestCase):
                                         _SERVER_HOST_OVERRIDE,
                                     ),)))
 
+    def tearDown(self):
+        self.server.stop(None)
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)