Fix Setter lookup

pkg/kernel/lib/interpreter/interpreter.dart

Index: pkg/kernel/lib/interpreter/interpreter.dart
diff --git a/pkg/kernel/lib/interpreter/interpreter.dart b/pkg/kernel/lib/interpreter/interpreter.dart
index a64fe581f12f7be928f4f34308138c6a63545c48..76e78d80fc848560b1d8c46619306a99c10b8d0e 100644
--- a/pkg/kernel/lib/interpreter/interpreter.dart
+++ b/pkg/kernel/lib/interpreter/interpreter.dart
@@ -315,7 +315,7 @@ class Class {
   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);
   }