Add hierarchy utils and use them in search.

pkg/analysis_services/test/search/search_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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
-library services.src.search.search_engine_test;
+library test.services.src.search.search_engine;
 
 import 'dart:async';
 
 import 'package:analysis_services/index/index.dart';
 import 'package:analysis_services/index/local_memory_index.dart';
 import 'package:analysis_services/search/search_engine.dart';
 import 'package:analysis_services/src/search/search_engine.dart';
 import 'package:analysis_testing/mocks.dart';
 import 'package:analysis_testing/reflective_tests.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 630 matching lines @@
         pattern).then((List<SearchMatch> matches) {
       _assertMatches(matches, expectedMatches);
     });
   }
 
   static void _assertMatches(List<SearchMatch> matches,
       List<ExpectedMatch> expectedMatches) {
     expect(matches, unorderedEquals(expectedMatches));
   }
 }