message: [XLA] Fix heap use after free in logging.
  Visitors can delete instructions, so it's not safe to access the instruction if
  visited.
diff: @@ -2987,8 +2987,8 @@ static Status PostOrderDFS(HloInstruction* root, Visitor* visitor,
  visitor->GetVisitState(current_id);
  if (visit_state == Visitor::kVisited) {
  dfs_stack.pop_back();
  - VLOG(3) << "Not visiting HLO %" << current_node->name()
  - << " as it was already visited.";
  + VLOG(3) << "Not visiting HLO (id = " << current_id
  + << ") as it was already visited.";
  continue;
  }
  