Clean up FunctionTypeUtils.isOfType method

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/BeanFactoryAwareFunctionRegistryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2019 the original author or authors.
+ * Copyright 2019-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -482,7 +482,7 @@ public class BeanFactoryAwareFunctionRegistryTests {
 
 		@Bean
 		public Consumer<String> imperativeConsumer() {
-			return null;
+			return System.out::println;
 		}
 
 		@Bean