[8u40] Request for approval: JDK-8067219: NPE in ScriptObject.clone() when running with object fields

[Hannes Wallnoefer]

Sorry for this last-minute request. I'd like to backport of JDK-8067219 
to 8u40.

Changes apply cleanly to 8u40 after shuffling path names.

Bug: https://bugs.openjdk.java.net/browse/JDK-8067219
Webrev: http://cr.openjdk.java.net/~hannesw/8067219/
Review thread: 
http://mail.openjdk.java.net/pipermail/nashorn-dev/2014-December/004017.html
Changeset: http://hg.openjdk.java.net/jdk9/dev/nashorn/rev/c4c3be2ab854

Thanks,
Hannes