Description:
------------
ReflectionFunction::getParameters() for built-in function array_unique returns one parameter, although in practice the function accepts two parameters (and documentation states the same).

https://3v4l.org/Tj5cj

Test script:
---------------
<?php

$ref = new ReflectionFunction('array_unique');
var_dump(count($ref->getParameters())); // outputs "1" in the PHP runtime

Expected result:
----------------
int(2)

Actual result:
--------------
int(1)