Remove unused implementation of SearchEngine and rename the driver-based implementation

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.
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
-import 'package:analysis_server/src/services/search/search_engine_internal2.dart';
+import 'package:analysis_server/src/services/search/search_engine_internal.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart' show Element;
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/ast_provider_driver.dart';
 import 'package:analyzer/src/dart/element/ast_provider.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     show
         RefactoringProblem,
         RefactoringProblemSeverity,
@@ skipping 142 matching lines @@
   Future<Null> indexTestUnit(String code) async {
     await resolveTestUnit(code);
   }
 
   Future<Null> indexUnit(String file, String code) async {
     addSource(file, code);
   }
 
   void setUp() {
     super.setUp();
-    searchEngine = new SearchEngineImpl2([driver]);
+    searchEngine = new SearchEngineImpl([driver]);
     astProvider = new AstProviderForDriver(driver);
   }
 }