[php-src] Issue #15165: There is no built in function for check serialize data like json_validate() came recently

Issue: https://github.com/php/php-src/issues/15165 Author: iftakharul-xs ### Description ```php $data = 'some string'; if (is_string($data) && @unserialize($data) !== false) { var_dump(unserialize($data)); } else { var_dump('Not a serialized string'); } ``` omitting the error is recommended by some platforms in a scenario, we're storing the serialized data in database somehow user altered the serilized data and php default behavior didn't wrok as expected php is giving this notice **Notice: unserialize(): Error at offset 0 of 11 bytes in tempCodeRunnerFile.php on line 6**