Revert "amberc: Load es2015-polyfills directly. TODO better."

This reverts commit 369e21ab7410a5dbb386b0519d2de1069458c7c4.

Gruntfile.js

@@ -40,7 +40,6 @@ module.exports = function (grunt) {
         amberc: {
             options: {
                 amber_dir: process.cwd(),
-                configFile: "config.js",
                 closure_jar: ''
             },
             amber: {

external/amber-dev/lib/amberc.js

@@ -202,10 +202,7 @@ function collect_st_files(configuration) {
  */
 function create_compiler(configuration) {
     var include_files = configuration.load;
-    return new Promise(configuration.requirejs.bind(null, ["amber/es2015-polyfills"]))
-        .then(function () {
-            return new Promise(configuration.requirejs.bind(null, ["amber/lang", "amber_core/Platform-Node"]));
-        })
+    return new Promise(configuration.requirejs.bind(null, ["amber/lang", "amber_core/Platform-Node"]))
         .then(function (boot) {
             configuration.core = boot.api;
             configuration.globals = boot.globals;