Test fix for new dart2js hints default.

pkg/analyzer/test/src/task/dart_test.dart

 // Copyright (c) 2015, 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.
 
 library test.src.task.dart_test;
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 1821 matching lines @@
 ''');
     LibrarySpecificUnit target = new LibrarySpecificUnit(source, source);
     computeResult(target, HINTS);
     expect(task, new isInstanceOf<GenerateHintsTask>());
     // validate
     _fillErrorListener(HINTS);
     errorListener.assertErrorsWithCodes(<ErrorCode>[HintCode.MISSING_RETURN]);
   }
 
   test_perform_dart2js() {
+    AnalysisOptionsImpl options = new AnalysisOptionsImpl();
+    options.dart2jsHint = true;
+    prepareAnalysisContext(options);
     Source source = newSource(
         '/test.dart',
         '''
 main(p) {
   if (p is double) {
     print('double');
   }
 }
 ''');
     LibrarySpecificUnit target = new LibrarySpecificUnit(source, source);
@@ skipping 985 matching lines @@
   /**
    * Fill [errorListener] with [result] errors in the current [task].
    */
   void _fillErrorListener(ResultDescriptor<List<AnalysisError>> result) {
     List<AnalysisError> errors = task.outputs[result];
     expect(errors, isNotNull, reason: result.name);
     errorListener = new GatheringErrorListener();
     errorListener.addAll(errors);
   }
 }