Refactor object property chain to use property pairs. The patch

itself seems a step back, but the primary aim is opening future
optimization opportunities. The list of changes follows:

 - Property is changed to be an abstract type, which has type, flags,
   and a value. It does not have a name anymore and property pointers
   cannot be compressed.
 - Full (32 bit) ecma values can be property values. This allows
   using non-compressed pointers for ecma values in the future.
 - The property chain is not restricted to the same item anymore,
   it can contain hash maps, arrays in the future.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/ecma/builtin-objects/ecma-builtin-json.c

@@ -1440,7 +1440,7 @@ ecma_builtin_json_object (ecma_object_t *obj_p, /**< the object*/
 
       JERRY_ASSERT (ecma_is_property_enumerable (property_p));
 
-      if (property_p->flags & ECMA_PROPERTY_FLAG_NAMEDDATA)
+      if (ECMA_PROPERTY_GET_TYPE (property_p) == ECMA_PROPERTY_TYPE_NAMEDDATA)
       {
         ecma_append_to_values_collection (property_keys_p, *iter.current_value_p, true);
       }