revert: feat: do not depend on babel-polyfill

This reverts commit db11d56.

config/babel.js

@@ -1,8 +1,5 @@
 'use strict'
 
 module.exports = {
-  plugins: [[require.resolve('babel-plugin-transform-runtime'), {
-    regenerator: false
-  }]],
   presets: [require.resolve('babel-preset-es2015')]
 }

config/karma.conf.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const path = require('path')
 const webpackConfig = require('./webpack')
 const timeout = webpackConfig.timeout
 
@@ -25,6 +26,7 @@ module.exports = function (config) {
       }
     },
     files: [
+      path.join(require.resolve('babel-polyfill'), '/../../dist/polyfill.js'),
       'test/browser.js',
       'test/**/*.spec.js'
     ],

config/webpack.js

@@ -31,6 +31,7 @@ const specific = merge(custom1, custom2)
 
 const shared = {
   entry: [
+    require.resolve('babel-polyfill'),
     path.resolve('src/index.js')
   ],
   output: {

package.json

@@ -27,7 +27,7 @@
     "args-parser": "^1.0.2",
     "babel-core": "^6.11.4",
     "babel-loader": "^6.2.4",
-    "babel-plugin-transform-runtime": "^6.12.0",
+    "babel-polyfill": "^6.9.1",
     "babel-preset-es2015": "^6.9.0",
     "brfs": "^1.4.3",
     "chalk": "^1.1.3",
@@ -92,4 +92,4 @@
     "Stephen Whitmore <stephen.whitmore@gmail.com>",
     "greenkeeperio-bot <support@greenkeeper.io>"
   ]
-}
+}