libweston: skip view which doesn't touch the output, in compositor_accumulate_damage()

Since repaint is called for each output, a view which doesn't touch the
output need to be skipped in compositor_accumulate_damage().
2 jobs for skip-not-touched-view in 5 minutes and 1 second (queued for 1 second)
latest
Status Job ID Name Coverage
  Container Prep
passed #570650
container_prep

00:03:55

 
  Build
passed #570651
build-native-meson

00:01:05