Description:
------------
next() does not advance the internal array pointer, if it is run on global variable inside function.

Reproduce code:
---------------
global $test;
$test=array(1=>'one',2=>'two',3=>'three');
function test() {
  global $test;
  echo current($test)."\n";
  next($test);
  echo current($test)."\n";
  next($test);
  echo current($test)."\n";
}
test();

Expected result:
----------------
one
two
three

Actual result:
--------------
one
one
one