Make sure XML filter comes with Woodstox dependency

XML input filter stream assume the XMLInputFactory is thread safe which is true in Woodstox implementation but not enforced by the XMLInputFactory specification.

XWiki do come with Woodstox but xwiki-commons-filter-xml does not enforce it right while it would be safer. It also means that right now xwiki-commons-filter-xml tests are not executed with woodstox so they don't reflex the runtime behavior.