Description:
------------
Array internal pointer does't work propely when passed to a function by reference.

Reproduce code:
---------------
$t = array('firstName' => 'Yanik', 'lastName' => 'Lupien');

// Cause an infinit loop, always display first key
function test(&$t) {
 for(reset($t); !is_null($key = key($t)); next($t)) {
  print "{$key}<br/>";	
 }
}

//Work well
for(reset($t); !is_null($key = key($t)); next($t)) {
	print "{$key}<br/>";	
}

// Infinit loop
test($t);

Expected result:
----------------
firstName
lastName
firstName
lastName


Actual result:
--------------
firstName
lastName
firstName
firstName
firstName
firstName
firstName
firstName
...