cxxrtl: allow `always` sync rules in debug_eval.
cxxrtl: allow `always` sync rules in debug_eval.

These can be produced from `always @*` processes, if `-noproc`
is used.

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