code: protected void compareProcessingInstruction(ProcessingInstruction control,
                                                  ProcessingInstruction test, DifferenceListener listener)
          throws DifferenceFoundException {
          compare(control.getTarget(), test.getTarget(), control, test, listener,
                  PROCESSING_INSTRUCTION_TARGET);
          compare(control.getData(), test.getData(), control, test, listener,
                  PROCESSING_INSTRUCTION_DATA);
      }
docs: Compare two processing instructions
  @param control
  @param test
  @param listener
  @throws DifferenceFoundException