xAODRootAccess: Work around pyroot method resolution issue.
As of root 6.18, when we try to call TPyEvent::record() from TPyEvent.py, we actually end up calling the base class method TEvent::record(), which has a compatible signature.
As a workaround, add a dummy argument to TPyEvent::record() to distinguish between the two signatures.
(This doesn't show up as an error in the release build because the relevant test is disabled.)