RFR: JDK-8289798: Update to use jtreg 7

[Alan Bateman]

On Wed, 6 Jul 2022 08:24:21 GMT, Christian Stein <cstein at openjdk.org> wrote:

> Please review the change to update to using jtreg 7.
> 
> The primary change is to the `jib-profiles.js` file, which specifies the version of jtreg to use, for those systems that rely on this file. In addition, the `requiredVersion` has been updated in the various `TEST.ROOT` files.

Have you run all the tiers to make sure there aren't any issues?

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PR: https://git.openjdk.org/jdk/pull/9393