test: disable artifacts cache with composefs

layers restored from a tarball won't be converted to composefs so
disable the cache when using composefs.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

contrib/cirrus/setup_environment.sh

@@ -54,6 +54,10 @@ if [[ "$CI_DESIRED_STORAGE" = "composefs" ]]; then
     if [[ "$PRIV_NAME" == "root" ]]; then
         CI_DESIRED_COMPOSEFS="+composefs"
 
+        # artifacts restored from a tarball won't be stored correctly
+        # in composefs, so we need to disable this feature.
+        export NO_TEST_ARTIFACTS=true
+
         # KLUDGE ALERT! Magic options needed for testing composefs.
         # This option was intended for passing one arg to --storage-opt
         # but we're hijacking it to pass an extra option+arg. And it
@@ -213,6 +217,8 @@ mount -t tmpfs -o size=75%,mode=0700 none /var/lib/containers
 # shellcheck disable=SC2154
 showrun echo "Setting CI_DESIRED_STORAGE [=$CI_DESIRED_STORAGE] for *e2e* tests"
 echo "STORAGE_FS=$CI_DESIRED_STORAGE" >>/etc/ci_environment
+showrun echo "Setting NO_TEST_ARTIFACTS [=$NO_TEST_ARTIFACTS] for *e2e* tests"
+echo "NO_TEST_ARTIFACTS=$NO_TEST_ARTIFACTS" >>/etc/ci_environment
 
 # Required to be defined by caller: The environment where primary testing happens
 # shellcheck disable=SC2154