message: integration_tests: use atomic for thread-safety
diff: @@ -30,7 +30,7 @@ static void pause_and_resume(std::shared_ptr<Mission> mission);
  static constexpr int NUM_MISSION_ITEMS = 30;
  -static bool pause_already_done = false;
  +static std::atomic<bool> pause_already_done{false};
  TEST_F(SitlTest, MissionAddWaypointsAndFly)
  {
  