Fix HeaderResultMatchers#string(String, String) assert order

Issue: SPR-14004

spring-test/src/main/java/org/springframework/test/web/servlet/result/HeaderResultMatchers.java

@@ -89,7 +89,7 @@ public class HeaderResultMatchers {
 		return new ResultMatcher() {
 			@Override
 			public void match(MvcResult result) {
-				assertEquals("Response header " + name, result.getResponse().getHeader(name), value);
+				assertEquals("Response header " + name, value, result.getResponse().getHeader(name));
 			}
 		};
 	}