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

pkg/analysis_server/test/services/search/hierarchy_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.
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/search/hierarchy.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/element/element.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../abstract_single_unit.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(HierarchyTest);
   });
 }
 
 @reflectiveTest
 class HierarchyTest extends AbstractSingleUnitTest {
-  SearchEngineImpl2 searchEngine;
+  SearchEngineImpl searchEngine;
 
   void setUp() {
     super.setUp();
-    searchEngine = new SearchEngineImpl2([driver]);
+    searchEngine = new SearchEngineImpl([driver]);
   }
 
   test_getClassMembers() async {
     await _indexTestUnit('''
 class A {
   A() {}
   var ma1;
   ma2() {}
 }
 class B extends A {
@@ skipping 315 matching lines @@
     {
       Set<ClassElement> supers = getSuperClasses(classF);
       expect(supers, unorderedEquals([objectElement, classA]));
     }
   }
 
   Future<Null> _indexTestUnit(String code) async {
     await resolveTestUnit(code);
   }
 }