Fix KafkaMesListenerContTests for proper mocks

https://build.spring.io/browse/SK-SK20X-34/

**Cherry-pick to 1.3.x**

Author: artembilan

spring-kafka/src/test/java/org/springframework/kafka/listener/KafkaMessageListenerContainerTests.java

@@ -652,7 +652,7 @@ public void testBrokerDownEvent() throws Exception {
 	public void testNonResponsiveConsumerEventNotIssuedWithActiveConsumer() throws Exception {
 		ConsumerFactory<Integer, String> cf = mock(ConsumerFactory.class);
 		Consumer<Integer, String> consumer = mock(Consumer.class);
-		given(cf.createConsumer(isNull(), eq(""))).willReturn(consumer);
+		given(cf.createConsumer(isNull(), isNull())).willReturn(consumer);
 		ConsumerRecords records = new ConsumerRecords(Collections.emptyMap());
 		CountDownLatch latch = new CountDownLatch(20);
 		given(consumer.poll(anyLong())).willAnswer(i -> {