private static boolean containsRevokedMember(Set<PersistentID> missing, UUID revokedUUID) {
    for (PersistentID id : missing) {
      if (id.getUUID().equals(revokedUUID)) {
        return true;
      }
    }
    return false;
  }
this is a test hook to allow us to drive SystemAdmin functions without invoking main(), which
can call System.exit().
geode-core/src/main/java/org/apache/geode/internal/SystemAdmin.java