[8u40] Request for approval: JDK-8062386: Different versions of nashorn use same code cache directory

[Hannes Wallnoefer]

Please approve backport of JDK-8062386 to 8u40.

The patch applies cleanly to 8u40 after fixing path names.

Bug: https://bugs.openjdk.java.net/browse/JDK-8062386
Webrev: http://cr.openjdk.java.net/~hannesw/8062386/
Review thread: 
http://mail.openjdk.java.net/pipermail/nashorn-dev/2014-November/003810.html
Changeset: http://hg.openjdk.java.net/jdk9/dev/nashorn/rev/3fa7d5c6ed92

Thanks,
Hannes