TrackRecordingService: generate timestamps for TrackPoints in HandlerServer.

Part of #822.

src/androidTest/java/de/dennisguse/opentracks/services/handlers/HandlerServerTest.java

@@ -47,7 +47,7 @@ public class HandlerServerTest {
     @Test
     public void sendTrackPoint() throws InterruptedException {
         // given
-        TrackPoint trackPoint = new TrackPoint(TrackPoint.Type.TRACKPOINT);
+        TrackPoint trackPoint = new TrackPoint(TrackPoint.Type.TRACKPOINT, null);
         int accuracy = 50;
 
         // when

src/androidTest/java/de/dennisguse/opentracks/services/handlers/LocationHandlerTest.java

@@ -13,8 +13,11 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
+import org.mockito.Mockito;
 import org.mockito.junit.MockitoJUnitRunner;
 
+import java.time.Instant;
+
 import de.dennisguse.opentracks.content.data.TrackPoint;
 import de.dennisguse.opentracks.util.PreferencesUtils;
 
@@ -45,6 +48,9 @@ public class LocationHandlerTest {
         // Let's use default values.
         sharedPreferences.edit().clear().commit();
 
+        Mockito.when(handlerServer.createNow())
+                .thenReturn(Instant.now());
+
         //TODO REMOVE
 //        locationHandler.onSharedPreferenceChanged(context, sharedPreferences, context.getString(R.string.recording_gps_accuracy_key));
 //        locationHandler.onSharedPreferenceChanged(context, sharedPreferences, context.getString(R.string.min_recording_interval_key));