9p: darwin: Adjust assumption on virtio-9p-test

9p: darwin: Adjust assumption on virtio-9p-test

The previous test depended on the assumption that P9_DOTL_AT_REMOVEDIR
and AT_REMOVEDIR have the same value.

While this is true on Linux, it is not true everywhere, and leads to an
incorrect test failure on unlink_at, noticed when adding 9p to darwin:

Received response 7 (RLERROR) instead of 77 (RUNLINKAT)
Rlerror has errno 22 (Invalid argument)
**

ERROR:../tests/qtest/virtio-9p-test.c:305:v9fs_req_recv: assertion
failed (hdr.id == id): (7 == 77) Bail out!

ERROR:../tests/qtest/virtio-9p-test.c:305:v9fs_req_recv: assertion
failed (hdr.id == id): (7 == 77)

Signed-off-by: Fabian Franz <fabianfranz.oss@gmail.com>
[Will Cohen: - Add explanation of patch and description
               of pre-patch test failure]
Signed-off-by: Will Cohen <wwcohen@gmail.com>
Acked-by: Thomas Huth <thuth@redhat.com>
[Will Cohen: - Move this patch before 9p: darwin: meson
               patch to avoid qtest breakage during
               bisecting]
Signed-off-by: Will Cohen <wwcohen@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20220227223522.91937-11-wwcohen@gmail.com>
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>