Description:
------------
The method ReflectionFunction::invoke has one parameter which is variadic ( http://php.net/manual/en/reflectionfunction.invoke.php ), but by reflection the method and its parameter are described as non-variadic.

Here a portion of code showing the method accepts a variadic parameter:
<?php
class Foo {
    public function concat($var1, $var2) {
        return $var1.$var2;
    }
}
$r = new ReflectionMethod('Foo', 'concat');
$args = ['Hello ', 'world!'];
echo $r->invoke(new Foo(), ...$args);// prints "Hello world!"

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

$rf = new ReflectionMethod(ReflectionFunction::class, 'invoke');
var_dump($rf->isVariadic());
var_dump($rf->getParameters()[0]->isVariadic());

Expected result:
----------------
bool(true)
bool(true)

Actual result:
--------------
bool(false)
bool(false)