tests/cdrom-test: Test that -cdrom parameter is working

tests/cdrom-test: Test that -cdrom parameter is working

Commit 1454509726719e0933c800 recently broke the "-cdrom" parameter
on a couple of boards without us noticing it immediately. Thus let's
add a test which checks that "-cdrom" can at least be used to start
QEMU with certain machine types.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
Acked-By: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>