add new testartifact to image cache

This is needed by podman-container-tools/podman#25238

To avoid flakes we need to have the test artifacts in the cache
registry.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

Author: Luap99

cache_images/local-cache-registry

@@ -76,6 +76,10 @@ declare -a IMAGELIST=(
     registry:2.8.2
     registry:volume_omitted
     systemd-image:20240124
+    testartifact:20250206-single
+    testartifact:20250206-multi
+    testartifact:20250206-multi-no-title
+    testartifact:20250206-evil
     testdigest_v2s2
     testdigest_v2s2:20200210
     testimage:00000000