Description:
------------
This change looks to be introduced accidentaly in HEAD, and was MFHd by me times ago. the hasProperty() is currently using the __isset magic method, this doesn't look right from a reflection perspective. It must behaves like property_exists() that doesn't uses the magic stuff.

Reproduce code:
---------------
<?php

class foo {
	function __isset($a) {
		var_dump($a);		
		return 1;
	}
}

$x = new foo;
$ref = new ReflectionObject($x);
var_dump($ref->hasProperty('b'));


Expected result:
----------------
bool(false)

Actual result:
--------------
string(1) "b"
bool(true)