message: Replace sleep with std::this_thread::sleep_for in integration tests
diff: @@ -23,7 +23,7 @@ TEST_F(SitlTest, GeofenceInclusion)
  ASSERT_EQ(ret, ConnectionResult::SUCCESS);
  // Wait for system to connect via heartbeat.
  - sleep(2);
  + std::this_thread::sleep_for(std::chrono::seconds(2));
  System &system = dl.system();
  ASSERT_TRUE(system.has_autopilot());
  @@ -32,7 +32,7 @@ TEST_F(SitlTest, GeofenceInclusion)
  while (!telemetry->health_all_ok()) {
  LogInfo() << "waiting for system to be ready";
  - sleep(1);
  + std::this_thread::sleep_for(std::chrono::seconds(1));
  }
  LogInfo() << "System ready, let's start";
  @@ -56,7 +56,7 @@ TEST_F(SitlTest, GeofenceInclusion)
  if (_got_result) {
  break;
  }
  - sleep(1);
  + std::this_thread::sleep_for(std::chrono::seconds(1));
  }
  EXPECT_TRUE(_got_result);
  