RFR: 8313167: Update to use jtreg 7.3

[Jonathan Gibbons]

On Wed, 26 Jul 2023 09:06:19 GMT, Christian Stein <cstein at openjdk.org> wrote:

> Please review the change to update to using jtreg 7.3.
> 
> 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.
> 
> Testing: tier1-tier3 (tier4 and tier5 pending...)

Marked as reviewed by jjg (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/15037#pullrequestreview-1565493747