gitlab-ci.yml: Stop creating meson-logs artifact

The logs were useless, as the complete test suite log was printed to
stdout.

.gitlab-ci.yml

@@ -18,7 +18,3 @@ test-mutter:
     - 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 2 --verbose --no-stdsplit --wrap catchsegv
-  artifacts:
-    paths:
-      - build/
-    when: on_failure