qemurunner: Handle lack of data on run serial gracefully
This changes the behavior when data was not received over
the serial console when a command is run. With this the
socket is no longer closed but it throws and exception that
can handled in upper layers. With this the test can continue
without throwing errors for not having the socket anymore.
[YOCTO #8118]
Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
