ErrorResponse support in Spring MVC exception hierarchy

All Spring MVC exceptions from spring-web, now implement ErrorResponse
and expose HTTP error response information, including an RFC 7807 body.

See gh-27052

spring-webflux/src/test/java/org/springframework/web/reactive/DispatcherHandlerErrorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -84,7 +84,7 @@ public class DispatcherHandlerErrorTests {
 		StepVerifier.create(mono)
 				.consumeErrorWith(ex -> {
 					assertThat(ex).isInstanceOf(ResponseStatusException.class);
-					assertThat(ex.getMessage()).isEqualTo("404 NOT_FOUND \"No matching handler\"");
+					assertThat(ex.getMessage()).isEqualTo("404 NOT_FOUND");
 				})
 				.verify();