Remove TestHepMC efficiency checks from logParser since it's already tested in athena

Hi @sargyrop ,

as described in f1847261 TestHepMC checks on athena run on small number of events issue error while on a full stat run only a warning. Please see log in e.g.: /afs/cern.ch/user/o/olszewsk/workspace/public/evgen/tests/800022PbPb5TeV/. Maybe check is too restrictive? Maybe athena check in git could be improved?

Cheers, Andrzej