RFR: JDK-8289798: Update to use jtreg 7 [v3]

[Christian Stein]

> 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.

Christian Stein has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:

 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Revert junit.java
   
   Commit https://github.com/openjdk/jdk/commit/45c3e898ed538545921395372fe507e9111401e1 deleted this file
 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Update to new JUnit JAR file
   
   With version 7 of `jtreg` comes JUnit Platform 1.8.2 (also known as "JUnit 5.8.2").
   This change updates the hard-coded library tag value to the new JUnit JAR file.
   Therefore, it partly addresses https://bugs.openjdk.org/browse/JDK-8292316,
   in order to unblock the "Update to use jtreg 7" PR 9393:
   https://github.com/openjdk/jdk/pull/9393
 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Merge branch 'openjdk:master' into JDK-8289798-jtreg-7
 - Update github-actions.conf
 - ... and 1 more: https://git.openjdk.org/jdk/compare/486f90c1...468f0bd3

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Changes: https://git.openjdk.org/jdk/pull/9393/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9393&range=02
  Stats: 10 lines in 7 files changed: 0 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/9393.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9393/head:pull/9393

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