println and flatten are correct

ps3/src/.gdb_history

@@ -0,0 +1,2 @@
+l
+exit

ps3/src/tree.c

@@ -224,11 +224,12 @@ static node_t* constant_fold_operator(node_t* node)
 static node_t* simplify_println_statement(node_t* node)
 {
   assert(node->type == PRINTLN_STATEMENT);
-  node->type = PRINT_STATEMENT;
+  node_t *result = node_create(PRINT_STATEMENT, 1, node->children[0]);
   node_t *newline = node_create(STRING_LITERAL, 0);
-  newline->data.string_literal = "\"\\n\"";
-  append_to_list_node(node, newline);
-  return node;
+  newline->data.string_literal = strdup("\"\\n\"");
+  append_to_list_node(node->children[0], newline);
+  node_finalize(node);
+  return result;
 }
 
 // Flatten all LOCAL_VARIABLE_DELCARATION nodes in the block, by converting them