On Android geolocationError return PositionError object.

Summary:
Follow iOS implementation:
https://github.com/facebook/react-native/blob/master/Libraries/Geolocation/RCTLocationObserver.m#L325

and FIX #9710
Closes https://github.com/facebook/react-native/pull/9734

Differential Revision: D3819868

Pulled By: mkonicek

fbshipit-source-id: 3deb7d3d253d402bfcb88c6a94ca705128998748

Examples/UIExplorer/js/GeolocationExample.js

@@ -59,7 +59,7 @@ class GeolocationExample extends React.Component {
         var initialPosition = JSON.stringify(position);
         this.setState({initialPosition});
       },
-      (error) => alert(error),
+      (error) => alert(JSON.stringify(error)),
       {enableHighAccuracy: true, timeout: 20000, maximumAge: 1000}
     );
     this.watchID = navigator.geolocation.watchPosition((position) => {