Support running over input files that don't contain the legacy EventInfo

This mechanism is being back-ported from the master branch in order to support running Run-2 Trigger simulation in r21 over RDO files produced by r22, as it is explained in ATEAM-568

With these changes RDOtoRDOTrigger can run in r21 over r22 RDOs either in serial or in MP mode

RunTier0Tests was successful. The log is available on AFS at /afs/cern.ch/user/t/tsulaia/workspace/RunTier0Tests.log

Tag @rbielski