Review request for JDK-8134503: support ES6 parsing in Nashorn

[Hannes Wallnoefer]

Please review JDK-8134503: support ES6 parsing in Nashorn
http://cr.openjdk.java.net/~hannesw/8134503/webrev/

The original patch was contributed by Andreas Woess, I just did the 
integration into Nashorn tip.

Thanks,
Hannes