Reverse the sense of the flag to make it easier to find test that need to be converted

pkg/analysis_server/test/analysis/update_content_test.dart

 // Copyright (c) 2015, 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 test.analysis.updateContent;
 
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
@@ skipping 20 matching lines @@
 compilationUnitMatcher(String file) {
   return new _ArgumentMatcher_CompilationUnit(file);
 }
 
 @reflectiveTest
 class UpdateContentTest extends AbstractAnalysisTest {
   Map<String, List<String>> filesErrors = {};
   int serverErrorCount = 0;
   int navigationCount = 0;
 
+  @override
+  bool get enableNewAnalysisDriver => false;
+
   Index createIndex() {
     return new _MockIndex();
   }
 
   @override
   void processNotification(Notification notification) {
     if (notification.event == ANALYSIS_ERRORS) {
       var decoded = new AnalysisErrorsParams.fromNotification(notification);
       String _format(AnalysisError e) =>
           "${e.location.startLine}: ${e.message}";
@@ skipping 295 matching lines @@
 
   @override
   bool matches(arg) {
     return arg is CompilationUnit &&
         resolutionMap.elementDeclaredByCompilationUnit(arg).source.fullName ==
             file;
   }
 }
 
 class _MockIndex extends TypedMock implements Index {}