babel output difference between chrome56 and ie9

chrome56.js

'use strict';

require('core-js/modules/es7.string.pad-start');

require('core-js/modules/es7.string.pad-end');

require('core-js/modules/web.timers');

require('core-js/modules/web.immediate');

require('core-js/modules/web.dom.iterable');

function something() {
    return new Promise(resolve => resolve());
}

async function go() {
    const result = await something();
    return result;
}

ie9.js

'use strict';

var go = function () {
    var _ref = _asyncToGenerator(regeneratorRuntime.mark(function _callee() {
        var result;
        return regeneratorRuntime.wrap(function _callee$(_context) {
            while (1) {
                switch (_context.prev = _context.next) {
                    case 0:
                        _context.next = 2;
                        return something();

                    case 2:
                        result = _context.sent;
                        return _context.abrupt('return', result);

                    case 4:
                    case 'end':
                        return _context.stop();
                }
            }
        }, _callee, this);
    }));

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

require('core-js/modules/es6.typed.data-view');

require('core-js/modules/es6.typed.int8-array');

require('core-js/modules/es6.typed.uint8-array');

require('core-js/modules/es6.typed.uint8-clamped-array');

require('core-js/modules/es6.typed.int16-array');

require('core-js/modules/es6.typed.uint16-array');

require('core-js/modules/es6.typed.int32-array');

require('core-js/modules/es6.typed.uint32-array');

require('core-js/modules/es6.typed.float32-array');

require('core-js/modules/es6.typed.float64-array');

require('core-js/modules/es6.map');

require('core-js/modules/es6.set');

require('core-js/modules/es6.weak-map');

require('core-js/modules/es6.weak-set');

require('core-js/modules/es6.reflect.apply');

require('core-js/modules/es6.reflect.construct');

require('core-js/modules/es6.reflect.define-property');

require('core-js/modules/es6.reflect.delete-property');

require('core-js/modules/es6.reflect.get');

require('core-js/modules/es6.reflect.get-own-property-descriptor');

require('core-js/modules/es6.reflect.get-prototype-of');

require('core-js/modules/es6.reflect.has');

require('core-js/modules/es6.reflect.is-extensible');

require('core-js/modules/es6.reflect.own-keys');

require('core-js/modules/es6.reflect.prevent-extensions');

require('core-js/modules/es6.reflect.set');

require('core-js/modules/es6.reflect.set-prototype-of');

require('core-js/modules/es6.promise');

require('core-js/modules/es6.symbol');

require('core-js/modules/es6.object.assign');

require('core-js/modules/es6.object.is');

require('core-js/modules/es6.object.set-prototype-of');

require('core-js/modules/es6.function.name');

require('core-js/modules/es6.string.raw');

require('core-js/modules/es6.string.from-code-point');

require('core-js/modules/es6.string.code-point-at');

require('core-js/modules/es6.string.repeat');

require('core-js/modules/es6.string.starts-with');

require('core-js/modules/es6.string.ends-with');

require('core-js/modules/es6.string.includes');

require('core-js/modules/es6.regexp.flags');

require('core-js/modules/es6.regexp.match');

require('core-js/modules/es6.regexp.replace');

require('core-js/modules/es6.regexp.split');

require('core-js/modules/es6.regexp.search');

require('core-js/modules/es6.array.from');

require('core-js/modules/es6.array.of');

require('core-js/modules/es6.array.copy-within');

require('core-js/modules/es6.array.find');

require('core-js/modules/es6.array.find-index');

require('core-js/modules/es6.array.fill');

require('core-js/modules/es6.array.iterator');

require('core-js/modules/es6.number.is-finite');

require('core-js/modules/es6.number.is-integer');

require('core-js/modules/es6.number.is-safe-integer');

require('core-js/modules/es6.number.is-nan');

require('core-js/modules/es6.number.epsilon');

require('core-js/modules/es6.number.min-safe-integer');

require('core-js/modules/es6.number.max-safe-integer');

require('core-js/modules/es6.math.acosh');

require('core-js/modules/es6.math.asinh');

require('core-js/modules/es6.math.atanh');

require('core-js/modules/es6.math.cbrt');

require('core-js/modules/es6.math.clz32');

require('core-js/modules/es6.math.cosh');

require('core-js/modules/es6.math.expm1');

require('core-js/modules/es6.math.fround');

require('core-js/modules/es6.math.hypot');

require('core-js/modules/es6.math.imul');

require('core-js/modules/es6.math.log1p');

require('core-js/modules/es6.math.log10');

require('core-js/modules/es6.math.log2');

require('core-js/modules/es6.math.sign');

require('core-js/modules/es6.math.sinh');

require('core-js/modules/es6.math.tanh');

require('core-js/modules/es6.math.trunc');

require('core-js/modules/es7.array.includes');

require('core-js/modules/es7.object.values');

require('core-js/modules/es7.object.entries');

require('core-js/modules/es7.object.get-own-property-descriptors');

require('core-js/modules/es7.string.pad-start');

require('core-js/modules/es7.string.pad-end');

require('core-js/modules/web.timers');

require('core-js/modules/web.immediate');

require('core-js/modules/web.dom.iterable');

require('regenerator-runtime/runtime');

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"); }); }; }

function something() {
    return new Promise(function (resolve) {
        return resolve();
    });
}

lib.js

import 'babel-polyfill'

function something() {
    return new Promise(resolve => resolve())
}

async function go() {
    const result = await something()
    return result
}