Update InArray.php

in InArray validator
if haystack is an empty array, an exception 'haystack option is mandatory' is thrown
should be exact equality ===




<?php
$t = array();
if ($t == null) echo "null\n"; else echo "not null\n";




this code echoes null




<?php
$t = array();
if ($t === null) echo "null\n"; else echo "not null\n";




this code echoes not null
Update InArrayTest.php

array() is a valid empty haystack, null no
Update InArrayTest.php
Update InArrayTest.php

the test testSetEmptyHaystack is not anymore needed as null can't be set 
on the setHaystack function because of the array type needed and empty array 
is possible.
Merge pull request #4047 from fchastanet/patch-1

Update InArray.php
[#4047] Re-instated test

- Modified to work on a clean instance of InArray, to demonstrate what happens
  if the haystack is null and you attempt to retrieve it.
Merge branch 'hotfix/4047'

Close #4047