message: Fix a bug that kernel launch events are over calculated.
diff: @@ -94,10 +94,10 @@ StepEvents ConvertHostThreadsXPlaneToStepEvents(
  }
  StepEvents ConvertDeviceTraceXLineToStepEvents(const XLineVisitor& line) {
  - int64 correlation_id = -1;
  - int64 group_id = -1;
  StepEvents result;
  line.ForEachEvent([&](const XEventVisitor& event) {
  + int64 correlation_id = -1;
  + int64 group_id = -1;
  event.ForEachStat([&](const XStatVisitor& stat) {
  if (stat.Type() == StatType::kCorrelationId) {
  correlation_id = stat.IntValue();
  