ArraySubsetConstraint use invalid cast to array

[bburnichon]

Q	A
PHPUnit version	5.7
PHP version	all
Installation Method	Composer / PHAR

        //type cast $other & $this->subset as an array to allow
        //support in standard array functions.
        if ($other instanceof ArrayAccess) {
            $other = (array) $other;
        }

This actually only works with ArrayObject instances. See https://3v4l.org/ti4aY for simple implementation.