TrigCost: Skip empty events during CostAnalysis
Skip events in which only cost chain was active (empty monitored events)
before
HLT_noalg_CostMonDS_L1All,"RATE:Monitoring, BW:Other, ",100,1000,0.5183,16.67,100,0,0.3413,0.01139,4,0,0,0,0
after
HLT_noalg_CostMonDS_L1All,"RATE:Monitoring, BW:Other, ",40,400,0.5085,6.667,100,0,0.1346,0.004515,4,0,0,0,0
tagging @tamartin