desktop-shell: Re-position views when outputs change

When the last output is destroyed or when a new output is created after
the last output is destroyed, we need to re-position the views to ensure
that all the views are displayed on the output.

Fixes: wayland/weston#210

Signed-off-by: Harish Krupo <harishkrupo@gmail.com>
2 jobs for window_disappear_fix in 1 minute and 4 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Container Prep
passed #350344
container_prep

00:00:27

 
  Build
passed #350345
build-native-meson

00:00:36