public static boolean isUndefined(DataType dataType) {
		if (dataType instanceof DefaultDataType) {
			return true;
		}
		if (dataType instanceof Undefined) {
			return true;
		}
		return isUndefinedArray(dataType);
	}
Determine if the specified dataType is either a DefaultDataType, 
an Undefined data-type, or an Array of Undefined data-types.
@param dataType
@return true if dataType represents an undefined data-type in
its various forms, else false.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/Undefined.java