message: A single measurement is enough when using simulation
diff: @@ -320,7 +320,8 @@ static PyObject* TF_MeasureCosts(
  tensorflow::OpPerformanceList op_performance_data;
  tensorflow::StepStats step_stats;
  - tensorflow::grappler::MeasuringCostEstimator cost_measure(cluster.get(), 10, 0);
  + const int num_measurements = cluster->type() == "virtual" ? 1 : 10;
  + tensorflow::grappler::MeasuringCostEstimator cost_measure(cluster.get(), num_measurements, 0);
  tensorflow::grappler::Costs costs;
  tensorflow::Status status = _GetOpPerformanceDataAndRunTime(
  