Skip failing test until oneworld is shipped

Summary:
The buck install command fails when xcode_dmg is used in sandcastle hosts, meaning xcode is mounted somewhere other than /Applications.
Skip the connection test for now. I'll get oneworld working with it instead.

Reviewed By: passy

Differential Revision: D10231097

fbshipit-source-id: 16e320070f8b3fd4f56ff919bdd3ec47355e342c

src/__tests__/server.electron.js

@@ -41,7 +41,7 @@ test('servers starting at ports', done => {
   });
 });
 
-test(
+test.skip(
   'Layout plugin is connecting',
   done => {
     server.addListener('new-client', (client: Client) => {