Fix for "Unable to resolve module nullthrows"

Summary:
Recreated due to mistake with #7594.
Closes #7934

Differential Revision: D3391010

fbshipit-source-id: 7aad253d29f2272cfdaace1c1bb4f54a63faa353

Libraries/Experimental/WindowedListView.js

@@ -44,8 +44,8 @@ const ViewabilityHelper = require('ViewabilityHelper');
 const clamp = require('clamp');
 const deepDiffer = require('deepDiffer');
 const infoLog = require('infoLog');
-const invariant = require('invariant');
-const nullthrows = require('nullthrows');
+const invariant = require('fbjs/lib/invariant');
+const nullthrows = require('fbjs/lib/nullthrows');
 
 import type ReactComponent from 'ReactComponent';