Description:
------------
When you create a class by extending mysqli or mysqli_result and add a destructor to it (to automatically call mysqli::close, for instance), it doesn't get called when the object gets out of scope.

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

class test extends mysqli
{
    function __construct() { echo "born\n"; }
    function __destruct() { echo "died\n"; }
}

$test = new test;
unset($test);

?>


Expected result:
----------------
born
died

Actual result:
--------------
born