Description:
------------
When you try to reflect a closure that was created using ReflectionFunction/Method::getClosure() the reflection objects doesn't say it's a closure.

Test script:
---------------
<?php
class MyClass {
    public function method() {}
}

$object = new MyClass;
$reflector = new \ReflectionMethod($object, 'method');
$closure = $reflector->getClosure($object);

$closureReflector = new \ReflectionFunction($closure);

//expected bool(true) - got false
var_dump($closureReflector->isClosure());