Description:
------------
The REGIT_INVERTED flag which can be set through the RegexIterator::__construct() or RegexIterator::setMode() isn't inverting the current return value.

Test script:
---------------
<?php
$it = new \ArrayIterator(array("foo", "bar", "baz"));
$it = new \RegexIterator($it, "/^ba/", \RegexIterator::MATCH, 2);
print_r(iterator_to_array($it));


Expected result:
----------------
array(
   [0] => foo
)

Actual result:
--------------
Array
(
    [1] => bar
    [2] => baz
)