Fix dispatch on MemberSets to always go dynamic if needed.

frog/world.dart

 // Copyright (c) 2011, 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.
 
 /** The one true [World]. */
 World world;
 
 /**
  * Should be called exactly once to setup singleton world.
  * Can use world.reset() to reinitialize.
@@ skipping 134 matching lines @@
     assert(!member.isPrivate);
     if (member.isStatic) {
       if (member.declaringType.isTop) {
         _addTopName(member);
       }
       return;
     }
 
     var mset = _members[member.name];
     if (mset == null) {
-      mset = new MemberSet(member);
+      mset = new MemberSet(member, isVar:true);
       _members[mset.name] = mset;
     } else {
       mset.members.add(member);
     }
   }
 
   _addTopName(Named named) {
     var existing = _topNames[named.name];
     if (existing != null) {
       info('mangling matching top level name "${named.name}" in '
@@ skipping 272 matching lines @@
 
   withTiming(String name, f()) {
     final sw = new StopWatch();
     sw.start();
     var result = f();
     sw.stop();
     info('$name in ${sw.elapsedInMs()}msec');
     return result;
   }
 }