Description:
------------
The parameter of __autoload() is wrong when using a variable to instantiate a namespaced class with aliasing namespace.

Reproduce code:
---------------
<?php
//file 1
function __autoload($className){
    var_dump($className);
    //require($className.'.php');
    exit;
}
use Foo as Bar;
new Bar\SomeClass;
?>

<?php
//file 2
function __autoload($className){
    var_dump($className);
    //require($className.'.php');
    exit;
}
use Foo as Bar;
$class = 'Bar\SomeClass';
new $class;
?>



Expected result:
----------------
file 1:
string(13) "Foo\SomeClass" 
file 2:
string(13) "Foo\SomeClass" 

Actual result:
--------------
file 1:
string(13) "Foo\SomeClass" 
file 2:
string(13) "Bar\SomeClass"