Mark internal AccessorInfo properties as "special data properties"

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 4823243f2384b510771dd53a76dfa3bdb80c9471..93c2c02059f9dd74a6b20c5f68bd9b5606b5970f 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -10506,6 +10506,9 @@ class AccessorInfo: public Struct {
   inline bool all_can_write();
   inline void set_all_can_write(bool value);
 
+  inline bool is_special_data_property();
+  inline void set_is_special_data_property(bool value);
+
   inline PropertyAttributes property_attributes();
   inline void set_property_attributes(PropertyAttributes attributes);
 
@@ -10538,7 +10541,8 @@ class AccessorInfo: public Struct {
   // Bit positions in flag.
   static const int kAllCanReadBit = 0;
   static const int kAllCanWriteBit = 1;
-  class AttributesField: public BitField<PropertyAttributes, 2, 3> {};
+  static const int kSpecialDataProperty = 2;
+  class AttributesField : public BitField<PropertyAttributes, 3, 3> {};
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AccessorInfo);
 };