[8u60] RFA 8117883 and 8098808

[A. Sundararajan]

Please approve.

Bugs:

8117883 <https://bugs.openjdk.java.net/browse/JDK-8117883>: nasgen 
prototype, instance member count calculation is wrong
8098808 <https://bugs.openjdk.java.net/browse/JDK-8098808>: Convert 
Scope from interface to class

jdk8u-dev webrev: 
http://cr.openjdk.java.net/~sundar/8098080_8117883/8u60/webrev.00/

jdk9 review threads:

http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-June/004786.html
http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-June/004774.html

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

Thanks,
-Sundar