RFR 8169050: underscore_linker.js sample fails after dynalink changes for JDK-8168005

[Sundararajan Athijegannathan]

Please review http://cr.openjdk.java.net/~sundar/8169050/webrev.00/ for
https://bugs.openjdk.java.net/browse/JDK-8169050

PS. The failing sample exposed a bug in nashorn's
NashornCallSiteDescriptor.  I converted that sample as a test.

Thanks,

-Sundar