remove getInstanceCount usages

Summary:
This diffs removes the usages of getInstanceCount as it has been removed from yoga.
We will add event support in js later to handle these test cases

Reviewed By: davidaurelio

Differential Revision: D16560269

fbshipit-source-id: 52590c426faf87209f8635602b401fd5760af8ab

javascript/sources/entry-common.js

@@ -350,9 +350,6 @@ module.exports = (bind: any, lib: any): Yoga => {
     Layout: bind('Layout', Layout),
     Size: bind('Size', Size),
     Value: bind('Value', Value),
-    getInstanceCount(...args) {
-      return lib.getInstanceCount(...args);
-    },
     ...CONSTANTS,
   };
 };