.github: catch piglit results as artifacts

Also store the piglit results into the build artifacts, so we can now
easily look at them later.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

.github/workflows/build-xserver.yml

@@ -67,6 +67,8 @@ jobs:
                   name: build-logs
                   path: |
                       build/meson-logs/*
+                      build/test/piglit-results/*
+
             - name: ddx build check
               run:  .gitlab-ci/check-ddx-build.sh
             - name: manpage check
@@ -220,6 +222,8 @@ jobs:
                   name: build-logs-macos
                   path: |
                       build/meson-logs/*
+                      build/test/piglit-results/*
+
             - name: ddx build check
               run:  .gitlab-ci/check-ddx-build.sh
             - name: manpage check