Problem: it's still not a 100% check because the way real udev handles the
EVDEV_ABS overrides ignores any that are set through udev properties only. So
we manually have to trigger the keyboard builtin for our test device which
can give us false positives (e.g. it wouldn't have detected #424). But still,
it'll alert us if the actual overridden values are different to what we
expect.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
