gitlab-ci: Put HTML summary in artifacts for failed piglit jobs

This will make it easier to look at details of failed / skipped tests.

Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index cee7f05..6e5f692 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -473,6 +473,11 @@
 
 .piglit-test:
   extends: .test
+  artifacts:
+    when: on_failure
+    name: "$CI_JOB_NAME-$CI_COMMIT_REF_NAME"
+    paths:
+      - summary/
   variables:
     LIBGL_ALWAYS_SOFTWARE: 1
     PIGLIT_NO_WINDOW: 1