GeneratorFilters: Use Helper functions from TruthUtils in older GeneratorFilters classes

Generators/GeneratorFilters/src/BoostedHadTopAndTopPair.cxx

Generators/GeneratorFilters/src/Common.cxx

Generators/GeneratorFilters/src/DecaysFinalStateFilter.cxx

Generators/GeneratorFilters/src/ForwardProtonFilter.cxx

Generators/GeneratorFilters/src/FourLeptonInvMassFilter.cxx

Generators/GeneratorFilters/src/FourLeptonMassFilter.cxx

Generators/GeneratorFilters/src/HeavyFlavorHadronFilter.cxx

Generators/GeneratorFilters/src/HiggsFilter.cxx

Generators/GeneratorFilters/src/LeptonFilter.cxx

Generators/GeneratorFilters/src/LeptonPairFilter.cxx

Generators/GeneratorFilters/src/MultiElecMuTauFilter.cxx

Generators/GeneratorFilters/src/TTbarMassFilter.cxx

...ators/GeneratorFilters/src/TTbarPlusHeavyFlavorFilter.cxx

Generators/GeneratorFilters/src/TTbarWToLeptonFilter.cxx

Generators/GeneratorFilters/src/TTbarWithJpsimumuFilter.cxx

Generators/GeneratorFilters/src/TauFilter.cxx

Generators/GeneratorFilters/src/VBFForwardJetsFilter.cxx

Generators/GeneratorFilters/src/VBFMjjIntervalFilter.cxx

Generators/GeneratorFilters/src/ZtoLeptonFilter.cxx