protected Varnode getSingleVnStorage(VariableStorage vs) {
		Varnode[] vns = vs.getVarnodes();
		if (vns.length != 1) {
			Unfinished.TODO();
		}
		return vns[0];
	}
Assert variable storage is a single varnode, and get that varnode

@param vs the storage
@return the single varnode
Ghidra/Features/SystemEmulation/src/main/java/ghidra/pcode/emu/sys/UseropEmuSyscallDefinition.java