Fix equality of implicit closures in the Dart VM.

runtime/vm/object_store.h

Index: runtime/vm/object_store.h
===================================================================
--- runtime/vm/object_store.h	(revision 26064)
+++ runtime/vm/object_store.h	(working copy)
@@ -66,6 +66,11 @@
     function_type_ = value.raw();
   }
 
+  RawType* function_impl_type() const { return function_impl_type_; }
+  void set_function_impl_type(const Type& value) {
+    function_impl_type_ = value.raw();
+  }
+
   RawClass* type_class() const { return type_class_; }
   void set_type_class(const Class& value) { type_class_ = value.raw(); }
 
@@ -426,6 +431,7 @@
   RawClass* null_class_;
   RawType* null_type_;
   RawType* function_type_;
+  RawType* function_impl_type_;
   RawClass* type_class_;
   RawClass* type_parameter_class_;
   RawClass* bounded_type_class_;