Merge branch '21p3.Fatras_G4MS_ART_tests.update' into '21.3'

Update Fatras-based FastChainPU ART tests

See merge request !31298

Simulation/FastSimulation/FastChainPileup/test/test_FastChain_fatras_mc16a_ttbar.sh

@@ -24,7 +24,7 @@ FastChain_tf.py \
     --conditionsTag default:OFLCOND-MC16-SDR-16 \
     --preSimExec 'from TrkDetDescrSvc.TrkDetDescrJobProperties import TrkDetFlags;TrkDetFlags.TRT_BuildStrawLayers=True;from Digitization.DigitizationFlags import digitizationFlags;digitizationFlags.experimentalDigi=["NewMerge"]' \
     --preExec 'EVNTtoRDO:ToolSvc.NewMergeMcEventCollTool.OutputLevel=VERBOSE;' \
-    --postInclude='PyJobTransforms/UseFrontier.py' \
+    --postInclude='PyJobTransforms/UseFrontier.py,G4AtlasTests/postInclude.SplitSG_FCpileup.py' \
     --postExec 'from AthenaCommon.ConfigurationShelve import saveToAscii;saveToAscii("config.txt");ServiceMgr.MessageSvc.Format = "% F%32W%S%7W%R%T %0W%M"' \
     --DataRunNumber '284500' \
     --inputHighPtMinbiasHitsFile ${HighPtMinbiasHitsFiles} \

Simulation/FastSimulation/FastChainPileup/test/test_fastchain_g4ms_mc16a_ttbar.sh

@@ -24,7 +24,7 @@ FastChain_tf.py \
     --conditionsTag default:OFLCOND-MC16-SDR-16 \
     --preSimExec 'from TrkDetDescrSvc.TrkDetDescrJobProperties import TrkDetFlags;TrkDetFlags.TRT_BuildStrawLayers=True;from Digitization.DigitizationFlags import digitizationFlags;digitizationFlags.experimentalDigi=["NewMerge"]' \
     --preExec 'EVNTtoRDO:ToolSvc.NewMergeMcEventCollTool.OutputLevel=VERBOSE;' \
-    --postInclude='PyJobTransforms/UseFrontier.py' \
+    --postInclude='PyJobTransforms/UseFrontier.py,G4AtlasTests/postInclude.SplitSG_FCpileup.py' \
     --postExec 'from AthenaCommon.ConfigurationShelve import saveToAscii;saveToAscii("config.txt");ServiceMgr.MessageSvc.Format = "% F%32W%S%7W%R%T %0W%M"' \
     --DataRunNumber '284500' \
     --inputHighPtMinbiasHitsFile ${HighPtMinbiasHitsFiles} \