ci: Run whole run-tests.sh in a D-Bus session

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1698>

.gitlab-ci.yml

@@ -254,7 +254,8 @@ build-without-native-backend-and-wayland@x86_64:
     MALLOC_CHECK_: "3"
     NO_AT_BRIDGE: "1"
   script:
-    - bash -x ./.gitlab-ci/run-tests.sh
+    - mkdir -m 700 $XDG_RUNTIME_DIR
+    - dbus-run-session -- bash -x ./.gitlab-ci/run-tests.sh
   artifacts:
     expire_in: 1 day
     reports:

.gitlab-ci/run-tests.sh

@@ -3,13 +3,10 @@
 set +e
 
 dconf update
-
-mkdir -m 700 $XDG_RUNTIME_DIR
 glib-compile-schemas $GSETTINGS_SCHEMA_DIR
 
 export MUTTER_DEBUG_DUMMY_MODE_SPECS="800x600@10.0"
 
-dbus-run-session -- \
 xvfb-run -s '+iglx -noreset' \
     meson test -C build --no-rebuild -t 10 --wrap catchsegv