This patch ported many tests to the new methodology, where the guest log
will be printed only when the test is failing.
Things to finish in follow-up PRs:
1. Special tests not ported yet include: test_reboot,
test_bzimage_reboot, test_serial_null(), test_serial_tty(),
test_serial_file(), test_virtio_console(), test_console_file(),
and test_simple_launch.
2. Few direct calls to 'Command::new(clh_command("cloud-hypervisor"))',
which is still printing the guest console
Signed-off-by: Bo Chen <chen.bo@intel.com>