Description:
------------
When using array_multisort in a funciton, and the array is set to "global", array_multisort fails to sort the array.

Reproduce code:
---------------
function does_work() {
    $data = array('first', 'fifth', 'second', 'forth', 'third');
    $sort = array(1, 5, 2, 4, 3);
    array_multisort($sort, $data);
    print_r($data);
}

function does_not_work() {
    global $data;
    $data = array('first', 'fifth', 'second', 'forth', 'third');
    $sort = array(1, 5, 2, 4, 3);
    array_multisort($sort, $data);
    print_r($data);
}

echo "function does_work():\n";
does_work();

echo "\n\nfunction does_not_work():\n";
does_not_work();

Expected result:
----------------
function does_work():
Array
(
    [0] => first
    [1] => second
    [2] => third
    [3] => forth
    [4] => fifth
)


function does_not_work():
Array
(
    [0] => first
    [1] => second
    [2] => third
    [3] => forth
    [4] => fifth
)

Actual result:
--------------
function does_work():
Array
(
    [0] => first
    [1] => second
    [2] => third
    [3] => forth
    [4] => fifth
)


function does_not_work():
Array
(
    [0] => first
    [1] => fifth
    [2] => second
    [3] => forth
    [4] => third
)