[8u-dev] RFA (XS): 8129822: Define "headful" jtreg keyword

[Hohensee, Paul]

A trivial backport that’s a pre-requisite for the JDK-8207070 backport. I added the jdk8u-fix-request to the JBS issue, but am posting here in the hope of a quick response. :)

JBS: https://bugs.openjdk.java.net/browse/JDK-8129822
Webrev: http://cr.openjdk.java.net/~phh/8129822/webrev.8u.00/
Original patch: http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/65f38133842d
Original review thread: http://mail.openjdk.java.net/pipermail/2d-dev/2015-June/005522.html

Patch applies cleanly.

Thanks,

Paul