xaiger: remove some unnecessary operations ...
xaiger: remove some unnecessary operations ...

... since they can not be triggered by (* keep *) anymore
(but could still be triggered by (* abc9_scc *) !?!)

YosysHQ/yosys,YosysHQ/yosys,YosysHQ/yosys,YosysHQ/yosys,YosysHQ/yosys,antmicro/yosys,antmicro/yosys,cliffordwolf/yosys,antmicro/yosys,cliffordwolf/yosys,cliffordwolf/yosys,YosysHQ/yosys,SymbiFlow/yosys,SymbiFlow/yosys,antmicro/yosys,SymbiFlow/yosys,cliffordwolf/yosys,SymbiFlow/yosys,cliffordwolf/yosys,cliffordwolf/yosys,antmicro/yosys,YosysHQ/yosys,antmicro/yosys,SymbiFlow/yosys,antmicro/yosys,SymbiFlow/yosys,antmicro/yosys,cliffordwolf/yosys,SymbiFlow/yosys,YosysHQ/yosys,cliffordwolf/yosys,SymbiFlow/yosys,cliffordwolf/yosys