add some packages

node_modules/core-js/modules/es6.string.iterator.js

@@ -0,0 +1,17 @@
+'use strict';
+var $at = require('./_string-at')(true);
+
+// 21.1.3.27 String.prototype[@@iterator]()
+require('./_iter-define')(String, 'String', function (iterated) {
+  this._t = String(iterated); // target
+  this._i = 0;                // next index
+// 21.1.5.2.1 %StringIteratorPrototype%.next()
+}, function () {
+  var O = this._t;
+  var index = this._i;
+  var point;
+  if (index >= O.length) return { value: undefined, done: true };
+  point = $at(O, index);
+  this._i += point.length;
+  return { value: point, done: false };
+});