RFR: 8313167: Update to use jtreg 7.3

[Christian Stein]

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...)

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Commit messages:
 - Use final tags for jtreg 7.3
 - Use CI build
 - Update to use jtreg 7.3
 - Use jtreg 7.3-ea release

Changes: https://git.openjdk.org/jdk/pull/15037/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15037&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313167
  Stats: 11 lines in 8 files changed: 0 ins; 0 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/15037.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15037/head:pull/15037

PR: https://git.openjdk.org/jdk/pull/15037