nixos/tests/redmine: Limit platforms to supported ones (#348178)

  realm = handleTest ./realm.nix {};

  redis = handleTest ./redis.nix {};

  redlib = handleTest ./redlib.nix {};

  redmine = handleTest ./redmine.nix {};

  redmine = handleTestOn [ "x86_64-linux" "aarch64-linux" ] ./redmine.nix {};

  renovate = handleTest ./renovate.nix {};

  replace-dependencies = handleTest ./replace-dependencies {};

  restartByActivationScript = handleTest ./restart-by-activation-script.nix {};