Add mu_mc grid test

Trigger/TrigValidation/TrigUpgradeTest/test/test_trigUpgr_slice_mu_mc_grid.sh

+#!/bin/bash
+# art-description: athenaMT trigger test on MC running L1 simulation and the muon menu
+# art-type: grid
+# art-include: master/Athena
+# art-output: *.log
+# art-output: *.new
+# art-output: *.txt
+# art-output: *.root
+
+export EVENTS=1000
+export THREADS=1
+export SLOTS=1
+export INPUT="run2mc_ttbar"
+export JOBOPTION="TrigUpgradeTest/full_menu.py"
+export REGTESTEXP="TriggerSummaryStep.*HLT_.*|TriggerMonitorFinal.*HLT_.*|TrigSignatureMoniMT.*HLT_.*"
+export EXTRA="doL1Sim=True;doEmptyMenu=True;doMuonSlice=True"
+
+
+source exec_TrigUpgradeTest_art_athenaMT.sh
+source exec_TrigUpgradeTest_art_post.sh