Deprecate the generated AST library and clean up imports

pkg/analysis_server/lib/src/status/validator.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 analysis_server.src.status.validator;
 
 import 'dart:collection';
 
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
+import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/element/element.dart';
-import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/engine.dart'
     show AnalysisEngine, AnalysisResult, CacheState, ChangeSet;
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_collection.dart';
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/src/task/html.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/model.dart';
@@ skipping 1734 matching lines @@
    * Determine whether or not there is any interesting difference between the
    * original and cloned values.
    */
   void _performComparison() {
     StringBuffer buffer = new StringBuffer();
     if (!_compareObjects(cloneValue, originalValue, buffer)) {
       description = buffer.toString();
     }
   }
 }