gitlab-ci: Use artifacts to keep built data and reuse in test

Make test to be dependent on build phase, saving artifacts for some time in
order to just run the tests without performing any rebuild.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/408

.gitlab-ci.yml

@@ -10,11 +10,22 @@ build-mutter:
     - meson . build -Dbuildtype=debugoptimized -Degl_device=true -Dwayland_eglstream=true --werror
     - ninja -C build
     - ninja -C build install
+  artifacts:
+    expire_in: 1 day
+    paths:
+      - build
 
 test-mutter:
   stage: test
+  dependencies:
+    - build-mutter
+  artifacts:
+    paths:
+      - build
   script:
-    - meson . build -Degl_device=true -Dwayland_eglstream=true
-    - ninja -C build
     - glib-compile-schemas $PWD/build/data
-    - env XDG_RUNTIME_DIR=/tmp/ GSETTINGS_SCHEMA_DIR=$PWD/build/data dbus-run-session -- xvfb-run -s '+iglx -noreset' meson test -C build -t 10 --verbose --no-stdsplit --wrap catchsegv
+    - >
+      env XDG_RUNTIME_DIR=/tmp
+      GSETTINGS_SCHEMA_DIR=$PWD/build/data
+      dbus-run-session -- xvfb-run -s '+iglx -noreset'
+      meson test -C build --no-rebuild -t 10 --verbose --no-stdsplit --wrap catchsegv