enable new analysis driver for completion sorter tests

pkg/analysis_server/test/domain_completion_util.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/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/domain_completion.dart';
@@ skipping 97 matching lines @@
       expect(allSuggestions.containsKey(id), isFalse);
       allSuggestions[id] = params.results;
       _getResultsCompleter(id).complete(null);
     } else if (notification.event == SERVER_ERROR) {
       fail('server error: ${notification.toJson()}');
     }
   }
 
   @override
   void setUp() {
+    enableNewAnalysisDriver = true;
     super.setUp();
     createProject();
     handler = new CompletionDomainHandler(server);
   }
 
   Completer<Null> _getResultsCompleter(String id) {
     return receivedSuggestionsCompleters.putIfAbsent(
         id, () => new Completer<Null>());
   }
 }