Fix ResourceRegion HttpMessageConverter write checks

This commit fixes the write checks for
`ResourceRegionHttpMessageConverter`, which was previously not checking
properly the parameterized type (e.g. in case of a `List<Something>`).

Issue: SPR-16932

spring-web/src/main/java/org/springframework/http/converter/ResourceRegionHttpMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -119,7 +119,7 @@ public class ResourceRegionHttpMessageConverter extends AbstractGenericHttpMessa
 		}
 
 		Class<?> typeArgumentClass = (Class<?>) typeArgument;
-		return typeArgumentClass.isAssignableFrom(ResourceRegion.class);
+		return ResourceRegion.class.isAssignableFrom(typeArgumentClass);
 	}
 
 	@Override