Description:
------------
is_array() does not work on member arrays of SimpleXMLElement objects.

Reproduce code:
---------------
<?php
$foo = simplexml_load_string(
'<?xml version="1.0" encoding="iso-8859-1" ?>

<foo>
  <bar>
    <barbara>barbara</barbara>
  </bar>
  <bar>
    <barbara>barbara</barbara>
    <barbara>barbara</barbara>
  </bar>
</foo>');

foreach ($foo->bar as $bar) {
    var_dump(is_array($bar->barbara));
    var_dump($bar);
}
?>

Expected result:
----------------
bool(false)
object(SimpleXMLElement)#4 (1) {
  ["barbara"]=>
  string(7) "barbara"
}
bool(true)
object(SimpleXMLElement)#5 (1) {
  ["barbara"]=>
  array(2) {
    [0]=>
    string(7) "barbara"
    [1]=>
    string(7) "barbara"
  }
}

Actual result:
--------------
bool(false)
object(SimpleXMLElement)#4 (1) {
  ["barbara"]=>
  string(7) "barbara"
}
bool(false)
object(SimpleXMLElement)#5 (1) {
  ["barbara"]=>
  array(2) {
    [0]=>
    string(7) "barbara"
    [1]=>
    string(7) "barbara"
  }
}