Deprecate the generated AST library and clean up imports

pkg/analysis_server/test/services/refactoring/abstract_refactoring.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 test.services.refactoring;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/index2/index2.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/search/search_engine_internal2.dart';
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../abstract_single_unit.dart';
 
 int findIdentifierLength(String search) {
   int length = 0;
   while (length < search.length) {
     int c = search.codeUnitAt(length);
     if (!(c >= 'a'.codeUnitAt(0) && c <= 'z'.codeUnitAt(0) ||
@@ skipping 129 matching lines @@
     CompilationUnit unit = resolveLibraryUnit(source);
     index.indexUnit(unit);
   }
 
   void setUp() {
     super.setUp();
     index = createMemoryIndex2();
     searchEngine = new SearchEngineImpl2(index);
   }
 }