removed tests directory to be more consistent with the latest rn

__tests__/App.tsx

@@ -1,12 +0,0 @@
-import 'react-native';
-import React from 'react';
-import App from '../App';
-
-// Note: test renderer must be required after react-native.
-import renderer from 'react-test-renderer';
-
-it('renders correctly', () => {
-  const tree = renderer.create(
-    <App />
-  );
-});