code: public static String[] getExecutorCommand(
        Config config,
        Config runtime,
        int shardId,
        Map<ExecutorPort, String> ports) {
      return getExecutorCommand(config, runtime, Integer.toString(shardId), ports);
    }
docs: Utils method to construct the command to start heron-executor
  
  @param config The static config
  @param runtime The runtime config
  @param shardId the executor/container index
  @param ports a map of ports to use where the key indicate the port type and the
  value is the port
  @return String[] representing the command to start heron-executor