fixed ERROR on duplicated sequences when using EmptyMenuSeuqences

...Validation/TrigUpgradeTest/share/EmuStepProcessingTest.py

...dation/TrigUpgradeTest/share/emu_step_menu_processing.ref

Trigger/TriggerCommon/TriggerJobOpts/python/TriggerConfig.py

...n/TriggerMenuMT/python/HLTMenuConfig/Menu/ChainMerging.py

...mon/TriggerMenuMT/python/HLTMenuConfig/Menu/LS2_emu_v1.py

...TriggerMenuMT/python/HLTMenuConfig/Menu/MenuComponents.py

...MenuMT/python/HLTMenuConfig/Test/GenerateTestChainDefs.py

...Common/TriggerMenuMT/python/HLTMenuConfig/Test/TestDef.py