Remove FATRAS for MS from ATLFASTIIF_G4MS
ATLFASTIIF_G4MS is supposed to use G4 in the MS, not FATRAS.
This patch removes ISF_MuonFatrasSelector from CaloSimulationSelectors,
improving level agreement between ATLFASTII and ATLFASTIIF_G4MS physics
results (with only a small hit in processing time); see here for plots.