Description:
------------
__set_state can't assign to inherited private properties but creates an new dynamic property.

Reproduce code:
---------------
class A {
	private $foo = 'foo';
	public static function __set_state($state) {
		$a = new A();
		$a->foo = 'bar';
		return $a;
	}
}
class B extends A {
	public static function __set_state($state) {
		$b = new B();
		$b->foo = 'bar';
		return $b;
	}
}
$a = A::__set_state(array());
$b = B::__set_state(array());
var_dump($a, $b);

Expected result:
----------------
object(A)#1 (1) {
  ["foo":"A":private]=>
  string(3) "bar"
}
object(B)#2 (2) {
  ["foo":"A":private]=>
  string(3) "bar"
}

Actual result:
--------------
object(A)#1 (1) {
  ["foo":"A":private]=>
  string(3) "bar"
}
object(B)#2 (2) {
  ["foo":"A":private]=>
  string(3) "foo"
  ["foo"]=>
  string(3) "bar"
}