Description:
------------
just a suggestion for short_open_tag

When it's ON, can parser ignore everything that is not "<?php", "<?=", "<? " i.e. like <?xml, <?blah ... etc.

and allow things like <?= work as designed

this is similar to bug/suggestion #26392

see example

Thanks

Reproduce code:
---------------
file: data.xml
<?xml version="1.0" ?>
<data>
<test><?=$value?></test>
</data>

file data.php
$value = 5;
include('data.xml'); // error


Expected result:
----------------
xml output with xml header

Actual result:
--------------
parser error