With the sdl frontend, qemu isn't able to even boot fully,
so let's skip the test early.
(From OE-Core rev: 74bb94a7d249b5c53f3e1d15688a3a323fc8e828)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>