RFR: JDK-8172241: Cleanup mistakes in jib publish support change

[Tim Bell]

Erik:

> This is a small followup fix for JDK-8170741. It addresses the following:
>
> * The new run-test-prebuilt profile is missing the JT_HOME environment
> variable from boot_jdk.
>
> * There are no compact profiles bundles to publish. I have created a new
> top level target to create these bundles and enabled publishing of them
> in jib-profiles.js.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8172241
>
> Webrev: http://cr.openjdk.java.net/~erikj/8172241/webrev.01/

Looks good.

Tim