message: Fix vm_hwm stats
  Summary: As title.
diff: @@ -1465,7 +1465,7 @@ int main(int argc, char* argv[]) {
  auto vm_stats = get_mem_stats();
  stats["output_stats"]["mem_stats"]["vm_peak"] =
  (Json::UInt64)vm_stats.vm_peak;
  - stats["output_stats"]["mem_stats"]["vm_hwm"] = (Json::UInt64)vm_stats.vm_peak;
  + stats["output_stats"]["mem_stats"]["vm_hwm"] = (Json::UInt64)vm_stats.vm_hwm;
  stats["output_stats"]["threads"] = get_threads_stats();
  