Further reduce use of Compiler.closedWorld.

tests/compiler/dart2js/simple_inferrer_final_field3_test.dart

 // Copyright (c) 2013, 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.
 
 // Test that we are analyzing field parameters correctly.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'compiler_helper.dart';
 import 'type_mask_test_helper.dart';
@@ skipping 10 matching lines @@
   new A();
   new A.bar('foo');
 }
 """;
 
 void main() {
   Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(TEST, uri);
   asyncTest(() => compiler.run(uri).then((_) {
         var typesInferrer = compiler.globalInference.typesInferrerInternal;
+        var closedWorld = typesInferrer.closedWorld;
 
         checkFieldTypeInClass(String className, String fieldName, type) {
           var cls = findElement(compiler, className);
           var element = cls.lookupLocalMember(fieldName);
           Expect.equals(type,
-              simplify(typesInferrer.getTypeOfElement(element), compiler));
+              simplify(typesInferrer.getTypeOfElement(element), closedWorld));
         }
 
-        checkFieldTypeInClass('A', 'dynamicField',
-            findTypeMask(compiler, 'Interceptor', 'nonNullSubclass'));
+        checkFieldTypeInClass(
+            'A', 'dynamicField', closedWorld.commonMasks.interceptorType);
       }));
 }