lib/x86: report result through serial console when no test device

If there are no test devices, we might be running on bare-metal or other
environment, in which port 0xF4, which reports the test result, is not
monitored. In such environments, print also the result of the test to
the serial console.

For realmode: just give a simple indication whether the test passed or
failed in a similar fashion.

This can allow automation tools to figure out the test is done and its
result.

Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
Message-Id: <20210609182945.36849-2-nadav.amit@gmail.com>