Reduce ecma_{ref, deref}_object calls while using ecma_builtin_get (#2616)

The following stucture was highly frequented in the code base:

 - Get a builtin object // This operation increases the reference count of the object
 - Use it for create a new object
 - Deref the builtin object

After a builtin has been instantiated there is always at least one reference to "keep it alive",
so increase/decrease the reference count for getting the value only is unnecessary.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

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

@@ -492,8 +492,6 @@ ecma_builtin_date_dispatch_construct (const ecma_value_t *arguments_list_p, /**<
   ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) obj_p;
   ext_object_p->u.class_prop.class_id = LIT_MAGIC_STRING_UNDEFINED;
 
-  ecma_deref_object (prototype_obj_p);
-
   if (arguments_list_len == 0)
   {
     ECMA_TRY_CATCH (parse_res_value,