Description:
------------
method_exists doesn't work if you pass in a callback with a reference to "self". Yet call_user_func *does* work if you pass in a callback with a reference to "self". This is inconsistent and probably not intentional.

Reproduce code:
---------------
<?php
class Test
{
    public static function check_method()
    {
        var_dump(method_exists('self', 'output'));
    }
    public static function run_method()
    {
        call_user_func(array('self', 'output'));
    }
    public static function output()
    {
        echo 'this works';
    }
}
Test::check_method();
Test::run_method();
?>

Expected result:
----------------
bool(true)
this works

Actual result:
--------------
bool(false)
this works