Removes dependency upon babel-polyfills (#2731)

* Removes runtime dependency babel-polyfill (#2692)

* Removes runtime dependency babel-polyfill

* removes references to polyfilled array includes

* Better support for polyfilling

* Removes unnecessary log

* Adds killswitch if tests are polyfilled

* Reverts usage of includes on strings

src/ParseServer.js

@@ -9,10 +9,6 @@ var batch = require('./batch'),
     path = require('path'),
     authDataManager = require('./authDataManager');
 
-if (!global._babelPolyfill) {
-  require('babel-polyfill');
-}
-
 import defaults                 from './defaults';
 import * as logging             from './logger';
 import AppCache                 from './cache';