babel bug with polyfill and async function in same module

.babelrc

{
  "presets": [
    [
      "env",
      {
        "targets": {
          "node": 4
        }
      }
    ]
  ]
}

babel-bug.dist.js

'use strict';

var foo = function () {
  var _ref = _asyncToGenerator(regeneratorRuntime.mark(function _callee() {
    return regeneratorRuntime.wrap(function _callee$(_context) {
      while (1) {
        switch (_context.prev = _context.next) {
          case 0:
          case 'end':
            return _context.stop();
        }
      }
    }, _callee, this);
  }));

  return function foo() {
    return _ref.apply(this, arguments);
  };
}();

function _asyncToGenerator(fn) { return function () { var gen = fn.apply(this, arguments); return new Promise(function (resolve, reject) { function step(key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { return Promise.resolve(value).then(function (value) { step("next", value); }, function (err) { step("throw", err); }); } } return step("next"); }); }; }

require('babel-polyfill');

babel-bug.source.js

require('babel-polyfill');

async function foo () {
}

exception.txt

$ node ./babel-bug.dist.js
/path/to/babel-bug.dist.js:4
  var _ref = _asyncToGenerator(regeneratorRuntime.mark(function _callee() {
                               ^

ReferenceError: regeneratorRuntime is not defined
    at /path/to/babel-bug.dist.js:4:32
    at Object.<anonymous> (/path/to/babel-bug.dist.js:19:2)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
    at tryModuleLoad (module.js:447:12)
    at Function.Module._load (module.js:439:3)
    at Module.runMain (module.js:605:10)
    at run (bootstrap_node.js:420:7)
    at startup (bootstrap_node.js:139:9)