MDL-66483 lib: remove recent xmlize dep on setuplib/CFG

This removes the dependency added by MDL-66110 (aiming to fix
a CI job). So we keep things as they were and will fix the
CI job separately.

lib/xmlize.php

@@ -39,9 +39,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-// Add setuplib in case it has not been loaded yet as it's required by \xml_format_exception.
-require_once($CFG->libdir.'/setuplib.php');
-
 class xml_format_exception extends moodle_exception {
     /** @var string */
     public $errorstring;