compositor: allow double-loading modules

This is necessary for the test harness to be able to execute the compositor
multiple times in the same process. As we never unload opened modules, the
first compositor iteration will leave them all loaded and following compositor
iterations will then have them already loaded.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
3 jobs for mr/reload in 2 minutes and 16 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Container Prep
passed #995548
container_prep

00:00:22

 
  Build
passed #995549
build-native-meson-default-options

00:01:15

passed #995550
build-native-meson-no-gl-renderer

00:00:38