Fix codegen hidden bugs

codegen/dbl_list/snippets/node_to_list

@@ -1,13 +1,11 @@
-  {T}List output = {{.first = node, .last = node, .total_size = node->string->size, .node_count = 1}};
+  {T}List output = {{.first = node, .last = node, .total_size = node->item->size, .node_count = 1}};
 
   while (output.first->prev != NULL) {{
-    output.total_size += output.first->prev->string->size;
     output.first = output.first->prev;
     ++(output.node_count);
   }}
 
   while (output.last->next != NULL) {{
-    output.total_size += output.last->next->string->size;
     output.last = output.last->next;
     ++(output.node_count);
   }}