XTS demo should fully exercise latest recovery API

The XTS demo does not currently fully exercise the recovery API because it is faking modifying and persisting changes of web service state via a local transactional resource. This means it does not need to link the prepare and commit cycle for the local state to the progress of the encompassing AT or BA web service transaction. In particular the new API methods introduced as part of JBTM-786 are not being exercised. The demo should be updated to employ a simple local transactional resource and to drive this resource correctly using the new API.