Remove Deprecated @babel/polyfill (parse-community#877)

* Remove Deprecated @babel/polyfill

* fix babel jest

* run against bleeding edge

Author: dplewis

babel-jest.js

@@ -4,7 +4,9 @@ module.exports = babelJest.createTransformer({
   presets: [["@babel/preset-env", {
     "targets": {
       "node": "8"
-    }
+    },
+    useBuiltIns: 'entry',
+    corejs: 3,
   }]],
   plugins: ['@babel/plugin-transform-flow-comments'],
 });

gulpfile.js

@@ -13,7 +13,7 @@ var BUILD = process.env.PARSE_BUILD || 'browser';
 var VERSION = require('./package.json').version;
 
 var transformRuntime = ["@babel/plugin-transform-runtime", {
-  "corejs": false,
+  "corejs": 3,
   "helpers": true,
   "regenerator": true,
   "useESModules": false