[php-src] Issue #13254: Typed optional parameter : default value break the type cheking

Issue: https://github.com/php/php-src/issues/13254 Author: SVGAnimate ### Description The following code: ```php <?php function polynomial(int $a=null) { $data = []; if ($a!=null) {// If $a hasn't been omited $data['a'] = $a; } return $data; } //$coefs = polynomial(); $coefs = polynomial(null);// f(x) = a.x + b //$coefs = polynomial(3); ``` Resulted in this output: ``` ``` But I expected this output instead: ``` Fatal error: Uncaught TypeError: polynomial(): Argument #1 ($a) must be of type int, null given ``` <hr/> The valide code: ```php <?php function polynomial(int $a=NAN) { } $coefs = polynomial(null); ``` Resulted in this output: ``` Fatal error: Uncaught TypeError: polynomial(): Argument #1 ($a) must be of type int, null given ``` ### PHP Version PHP 8.1.12 ### Operating System _No response_