Remove `MRB_TT_DATA` calculation of `memsize_of`; #5032

mrbgems/mruby-objectspace/src/mruby_objectspace.c

@@ -304,9 +304,6 @@ os_memsize_of_object(mrb_state* mrb, mrb_value obj, mrb_value recurse, mrb_int*
     }
     case MRB_TT_DATA:
       (*t) += mrb_objspace_page_slot_size();
-      if(mrb_respond_to(mrb, obj, mrb_intern_lit(mrb, "memsize"))) {
-        (*t) += mrb_fixnum(mrb_funcall(mrb, obj, "memsize", 0));
-      }
       break;
     #ifndef MRB_WITHOUT_FLOAT
     case MRB_TT_FLOAT:
@@ -390,11 +387,6 @@ os_memsize_of_object(mrb_state* mrb, mrb_value obj, mrb_value recurse, mrb_int*
  *  the final sum. It avoids infinite recursion and over counting objects by
  *  internally tracking discovered object ids.
  *
- *  MRB_TT_DATA objects aren't calculated beyond their original page slot. However,
- *  if the object implements a memsize method it will call that method and add the
- *  return value to the total. This provides an opportunity for C based data structures
- *  to report their memory usage.
- *
  */
 
 static mrb_value