test/system: Skip the test before doing any needless work

https://github.com/containers/toolbox/pull/1591

test/system/103-container.bats

@@ -50,16 +50,16 @@ teardown() {
 }
 
 @test "container(Fedora Rawhide): Containers with supported versions start without issues" {
+  if ! is_fedora_rawhide; then
+    skip "This test is only for Fedora Rawhide"
+  fi
+
   local system_id
   system_id="$(get_system_id)"
 
   local system_version
   system_version="$(get_system_version)"
 
-  if ! is_fedora_rawhide; then
-    skip "This test is only for Fedora Rawhide"
-  fi
-
   create_distro_container "$system_id" "$system_version" latest
   run container_started latest
   assert_success