Description:
------------
The same issue as Bug#21954,
that 'array_key_exists' warns for large numeric keys!

Bug#21954 is believed to be bogus,
but I don't think so!

From the manual of this function, it says that 
"key can be any value possible for an array index".

Since the statement '$a[2163195907] = "hi";' is acceptable for PHP, the function should accept 2163195907 as the argument 'key', too.

More, PHP is used as a type-less language, why should I bother from that?!

Reproduce code:
---------------
<?php
	$a = array();
	$a[2163195907] = "hi";
	echo array_key_exists(2163195907,$a);
?>

Expected result:
----------------
true

Actual result:
--------------
Warning: array_key_exists(): The first argument should be either a string or an integer in bug.php on line 4