[Reviewer: Rob] Gemini live tests

Rob, can you review these live tests for Gemini
I was briefly confused here, because our other SUBSCRIBE tests actually test the reg-event package, and this doesn't. Is it worth:
* renaming the "SIP SUBSCRIBE/NOTIFY" test to be clear that it tests the reg-event package?
* adding a comment to note that our SUBSCRIBEs here are just getting passed through? (Maybe not - the test definitions are reasonably obvious.)