Incorrect emit order in exporting

[falsandtru]

ts:

let f: any;
(() => f = () => 0)();
export {f} // f is defined

emit:

"use strict";
var f;
exports.f = f; // f is undefined
(function () { return f = function () { return 0; }; })();

[vladima]

duplicate of #4101

[falsandtru]

thanks!