message: don't create python trace if both host_tracer_level and python_tracer_level is 0, i.e. disabled.
diff: @@ -103,9 +103,12 @@ Status PythonTracer::CollectData(XSpace* space) {
  // Not in anonymous namespace for testing purposes.
  std::unique_ptr<ProfilerInterface> CreatePythonTracer(
  const ProfileOptions& options) {
  + if (options.python_tracer_level() == 0 && options.host_tracer_level() == 0) {
  + return nullptr;
  + }
  PythonHooksOptions pyhooks_options;
  pyhooks_options.enable_trace_python_function = options.python_tracer_level();
  - pyhooks_options.enable_python_traceme = options.host_tracer_level() != 0;
  + pyhooks_options.enable_python_traceme = options.host_tracer_level();
  return absl::make_unique<PythonTracer>(pyhooks_options);
  }
  