[8u60] approval request for 8081609: engine.eval call from a java method which was called from a previous engine.eval results in wrong ScriptContext being used.

[A. Sundararajan]

Please approve.

Bug: https://bugs.openjdk.java.net/browse/JDK-8081609
jdk9 review thread: 
http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-June/004634.html
jdk8u-dev webrev: http://cr.openjdk.java.net/~sundar/8081609/8u60/webrev.00/

Had to do manual change because another jdk9 only fix 
https://bugs.openjdk.java.net/browse/JDK-8059211 affected Global.java. 
I'm copying to jdk9 reviewers as well.

Thanks,
-Sundar