compositor: rebuild the global list if we've removed a surface from it

compositor: rebuild the global list if we've removed a surface from it

The list of surfaces used by weston_compositor_pick_surface() is
maintained in list of surfaces stored on the compositor. This list is
generated from the surfaces across all the layers using
weston_compositor_build_surface_list.

When destroying a surface the surface is "unmapped" with
weston_surface_unmap which removes it from the layer list. However since
the compositor surface list was only being rebuilt when the output was
repainted a call to weston_compositor_pick_surface before the next
output repaint would use an outdated surface list containing surfaces
that have been partially destroyed.

https://bugs.freedesktop.org/show_bug.cgi?id=65986
https://bugs.freedesktop.org/show_bug.cgi?id=66173
https://bugs.freedesktop.org/show_bug.cgi?id=66198