Type\Intersection does not work for > 3 types

[bendavies]

Hi

Related to #6

$foo = Type\intersection(
    Type\instance_of(Foo::class),
    Type\instance_of(Bar::class),
    Type\instance_of(Baz::class),
    Type\instance_of(Boo::class),
)->assert($foo);

the type of $foo
should be: Foo&Bar&Baz&Boo
but is: (Foo&Bar)|(Baz&Boo)

Thanks