Fix Setter lookup

pkg/kernel/lib/interpreter/interpreter.dart

 // Copyright (c) 2017, 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 kernel.interpreter;
 
 import '../ast.dart';
 import '../ast.dart' as ast show Class;
 
 class NotImplemented {
   String message;
@@ skipping 297 matching lines @@
   Getter lookupGetter(Name name) {
     Getter getter = getters[name];
     if (getter != null) return getter;
     if (superclass != null) return superclass.lookupGetter(name);
     return (Value receiver) => notImplemented(obj: name);
   }
 
   Setter lookupSetter(Name name) {
     Setter setter = setters[name];
     if (setter != null) return setter;
-    if (superclass != null) return lookupSetter(name);
+    if (superclass != null) return superclass.lookupSetter(name);
     return (Value receiver, Value value) => notImplemented(obj: name);
   }
 
   Value getProperty(ObjectValue object, Member member) {
     if (member is Field) {
       int index = instanceFields.indexOf(member);
       // TODO: throw NoSuchMethodError instead.
       if (index < 0) return notImplemented(m: 'NoSuchMethod: ${member}');
       return object.fields[index];
     }
@@ skipping 161 matching lines @@
 
 class NullValue extends LiteralValue {
   Object get value => null;
 
   const NullValue();
 }
 
 notImplemented({String m, Object obj}) {
   throw new NotImplemented(m ?? 'Evaluation for $obj is not implemented');
 }