[8u60] approval request for 8080090: -d option should dump script source as well

[A. Sundararajan]

Please approve.

Bug: https://bugs.openjdk.java.net/browse/JDK-8080090
8u-dev webrev: http://cr.openjdk.java.net/~sundar/8080090/8u60/
jdk9 review thread: 
http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-May/004512.html

Backported 'as is' except for modular source layout difference.

Thanks,
-Sundar