Fix kernel/visitor_test

pkg/compiler/lib/src/resolution/resolution.dart

 // Copyright (c) 2012, 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 dart2js.resolution;
 
 import 'dart:collection' show Queue;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
@@ skipping 407 matching lines @@
 
       if (Elements.isStaticOrTopLevelField(element)) {
         visitor.addDeferredAction(element, () {
           if (element.modifiers.isConst) {
             element.constant = constantCompiler.compileConstant(element);
           } else {
             element.constant = constantCompiler.compileVariable(element);
           }
         });
         if (initializer != null) {
-          if (!element.modifiers.isConst) {
+          if (!element.modifiers.isConst &&
+              initializer.asLiteralNull() == null) {
             // TODO(johnniwinther): Determine the const-ness eagerly to avoid
             // unnecessary registrations.
             registry.registerFeature(Feature.LAZY_FIELD);
           }
         }
       }
 
       // Perform various checks as side effect of "computing" the type.
       element.computeType(resolution);
 
@@ skipping 698 matching lines @@
   TreeElements get treeElements {
     assert(invariant(this, _treeElements != null,
         message: "TreeElements have not been computed for $this."));
     return _treeElements;
   }
 
   void reuseElement() {
     _treeElements = null;
   }
 }