Description:
------------
array_search() function finds non-existent element after array_slice() is used to slice the array.

tested on 5.2.0 and 5.2.5, don't have access to newer system.

Reproduce code:
---------------
$a["nazdar"] = "pozdrav";
$a["write"] = 1;
$a[2] = "ahoj";
$a = array_slice($a, 2);
$keys = array_keys($a);
echo "keys:\n"; var_dump($keys);
check_array_search("wrqwdite2", $keys);
function check_array_search($val, $keys)
{
        $i = array_search($val, $keys);
        if ($i === false) {
                echo "OK\n";
                return;
        }
        echo "BUG!!! Non-existent value \"$val\" found in keys at position $i!!!\n";
}


Expected result:
----------------
keys:
array(1) {
  [0]=>
  int(0)
}
OK

Actual result:
--------------
keys:
array(1) {
  [0]=>
  int(0)
}
BUG!!! Non-existent value "wrqwdite2" found in keys at position 0!!!