[8u20] approval request for 8044798: API for debugging Nashorn

[A. Sundararajan]

Please approve:

Bug: https://bugs.openjdk.java.net/browse/JDK-8044798
jdk9 webrev: http://cr.openjdk.java.net/~sundar/8044798/webrev.00/
jdk9 review thread: 
http://mail.openjdk.java.net/pipermail/nashorn-dev/2014-June/003069.html
jdk9 changeset: http://hg.openjdk.java.net/jdk9/dev/nashorn/rev/71cfc5012321

jdk8u20 webrev: http://cr.openjdk.java.net/~sundar/8044798/8u20/webrev.00/

I had to adjust changes slightly for jdk8. I'm CC'ing jdk9 reviewers to 
okay the same.

Changes are
*) patch wouldn't apply "as is" on DebuggerSupport due to jdk9 specific 
code in jdk9 - but the current diff is applied manually. But actual 
change is same.

*) JDK-8044798.js test adjusted to sort the output from valueInfosMethod 
so that the result is independent of order values of keys in the map 
returned by DebuggerSupport.valueInfos method.

Thanks
-Sundar