Put newly discovered devices to the bottom of the list

Add two type SortType.TYPE_DEFAULT and SortType.TYPE_FIFO in BluetoothDevicePreference.
It needs to decide the sort type when you create the BluetoothDevicePreference.
TYPE_DEFAULT - According to the CacheBluetoothDevice state to sort
TYPE_FIFO - According to the timestamp to sort

Bug: 112546918
Test: make -j42 RunSettingsRoboTests
Change-Id: Icd25d9b76a44d5a105f8daf64e5bc1f9ead8cd92

src/com/android/settings/bluetooth/DeviceListPreferenceFragment.java

@@ -191,7 +191,7 @@ public abstract class DeviceListPreferenceFragment extends
 
         if (preference == null) {
             preference = new BluetoothDevicePreference(getPrefContext(), cachedDevice,
-                    mShowDevicesWithoutNames);
+                    mShowDevicesWithoutNames, BluetoothDevicePreference.SortType.TYPE_FIFO);
             preference.setKey(key);
             //Set hideSecondTarget is true if it's bonded device.
             preference.hideSecondTarget(true);