Fix unit test errors in libphutil

Summary:
Now that we have automatic builds, libphutil is failing because these tests aren't working.

A while ago, we changed xhpast to parse the <?php token a bit differently. Some of the highlighting stuff needs to be updated for it.

Test Plan: Ran arc unit --everything.

Reviewers: joshuaspence, chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D14230