Description:
------------
The number of parameters returned by reflection is wrong for imagewebp().

See:
https://secure.php.net/manual/en/function.imagewebp.php


Test script:
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<?php
$rf = new ReflectionFunction('imagewebp');
var_dump($rf->getNumberOfParameters());
var_dump($rf->getNumberOfRequiredParameters());

Expected result:
----------------
int(3)
int(1)

Actual result:
--------------
int(2)
int(1)