[php-src] Issue #9194: can `$dom->createElement` return `false`

Issue: https://github.com/php/php-src/issues/9194 Author: staabm ### Description the docs suggest createElement() might return false. https://www.php.net/manual/en/domdocument.createelement.php looking at the source makes me think there is only a single case which might return false https://github.com/php/php-src/blob/c2a58ab07db1d004daa65646315d9bf63d208827/ext/dom/document.c#L531 I tried triggering this line, but then I got a exception, see https://3v4l.org/L35Q6 I am wondering whether the return false is no longer possible and the signature should be updated? ### PHP Version 8.1.x ### Operating System _No response_