message: Fix stats_summary output by swapping axis 1 and 2
diff: @@ -302,7 +302,7 @@ REGISTER_OP("BoostedTreesAggregateStats")
  DimensionHandle stats_dim;
  TF_RETURN_IF_ERROR(c->Add(logits_dim, hessian_dim, &stats_dim));
  c->set_output(
  - 0, c->MakeShape({max_splits, num_buckets, feature_dim, stats_dim}));
  + 0, c->MakeShape({max_splits, feature_dim, num_buckets, stats_dim}));
  return Status::OK();
  });
  