Make the analysis server integration tests driver only.

pkg/analysis_server/test/integration/search/find_element_references_test.dart

 // Copyright (c) 2017, 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/plugin/protocol/protocol.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ skipping 51 matching lines @@
   Future<List<SearchResult>> _findElementReferences(String text) async {
     int offset = text.indexOf(' /* target */') - 1;
     SearchFindElementReferencesResult result =
         await sendSearchFindElementReferences(pathname, offset, false);
     if (result.id == null) return null;
     SearchResultsParams searchParams = await onSearchResults.first;
     expect(searchParams.id, result.id);
     expect(searchParams.isLast, isTrue);
     return searchParams.results;
   }
-
-  @override
-  bool get enableNewAnalysisDriver => true;
 }