tests: implement touch in test-helpers

Let the client bind to wl_touch. Since we have our own seat,
we know that the compositor will have wl_touch capability.

v2: rebased due to changes in previous commit

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
2 files changed