message: Add a log message to inform user when graph optimization passes are being executed too many times and possible solution.
diff: @@ -32,6 +32,12 @@ void OptimizationPassRegistry::Register(
  Status OptimizationPassRegistry::RunGrouping(
  Grouping grouping, const GraphOptimizationPassOptions& options) {
  + LOG(INFO)
  + << "Running all optimization passes in grouping " << grouping
  + << ". If you see this a lot, you might be extending the graph too many "
  + "times (which means you modify the graph many times before "
  + "execution). Try reducing graph modifications or using SavedModel to "
  + "avoid any graph modification";
  auto group = groups_.find(grouping);
  if (group != groups_.end()) {
  for (auto& phase : group->second) {
  