[8u20] approval request for 8044612: StringIndexOutOfBoundException in NativeRegExp.appendReplacement

[A. Sundararajan]

Please approve backport to 8u20:

Bug: https://bugs.openjdk.java.net/browse/JDK-8044520
Webrev: http://cr.openjdk.java.net/~sundar/8044612/
jdk9 review thread: 
http://mail.openjdk.java.net/pipermail/nashorn-dev/2014-June/003029.html
jdk9 changeset: http://hg.openjdk.java.net/jdk9/dev/nashorn/rev/e445404a69f5

Thanks
-Sundar