run timezone and firewall tests in CI

Both tests work in CI just fine so we should run them every time. I
introduce them as a separate jobs because jobs run in parallel so it
takes less time even though it does not share object store.

samples/build-from-yum.json

@@ -14,7 +14,8 @@
         },
         "packages": [
           "dnf",
-          "systemd"
+          "systemd",
+          "tar"
         ]
       }
     }