Issue 27130. Fix applying changes to .analysis_options on save.

pkg/analyzer/test/generated/engine_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.test.generated.engine_test;
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 384 matching lines @@
   void addListener(AnalysisListener listener) {
     fail("Unexpected invocation of addListener");
   }
 
   @override
   void applyAnalysisDelta(AnalysisDelta delta) {
     fail("Unexpected invocation of applyAnalysisDelta");
   }
 
   @override
-  ApplyChangesStatus applyChanges(ChangeSet changeSet) {
+  void applyChanges(ChangeSet changeSet) {
     fail("Unexpected invocation of applyChanges");
     return null;
   }
 
   @override
   String computeDocumentationComment(Element element) {
     fail("Unexpected invocation of computeDocumentationComment");
     return null;
   }
 
@@ skipping 298 matching lines @@
   @override
   void test_flushAstStructures(Source source) {
     fail("Unexpected invocation of test_flushAstStructures");
   }
 
   @override
   void visitContentCache(ContentCacheVisitor visitor) {
     fail("Unexpected invocation of visitContentCache");
   }
 }