do not add nodes to backward list if inference only
do not add nodes to backward list if inference only

emjotde/amunn,DianaDespa/marian-train,emjotde/amunn,marian-nmt/marian-train,emjotde/amunmt,DianaDespa/marian-train,DianaDespa/marian-train,emjotde/amunmt,emjotde/amunmt,emjotde/Marian,amunmt/marian,amunmt/marian,emjotde/amunn,marian-nmt/marian-train,marian-nmt/marian-train,DianaDespa/marian-train,emjotde/amunmt,emjotde/Marian,marian-nmt/marian-train,amunmt/marian,marian-nmt/marian-train,DianaDespa/marian-train,emjotde/amunn