PHP vanilla vs PHP JIT

Hello,

PHP can JIT too using the `opcache` module.

On my linux system, with PHP 8.1.2 CLI :

**PHP Vanilla :**
`time php fib.php` 
=> 149 seconds

**PHP JIT :** 
`time php -dopcache.enable_cli=1 -dopcache.jit=function -dopcache.jit_buffer_size=500M fib.php`
=> 57 seconds
