Description:
------------
Passing a string or array reference to call_user_func gives an array in PHP 7, while it works fine in PHP 4 and PHP 5.

See http://3v4l.org/D9PjW#vphp7@20150101

Test script:
---------------
<?php
function l($m) {
    echo $m . "\n";
}
 
$cb = 'l';
call_user_func($cb, 'hi');
 
$cb2 = &$cb;
call_user_func($cb2, 'hi2');
?>


Expected result:
----------------
hi
hi2

Actual result:
--------------
hi
Warning: call_user_func() expects parameter 1 to be a valid callback, no array or string given in /in/D9PjW on line 10