RFR: 7904070: Update to use JUnit 5.13.4

[Christian Stein]

Please review this change updating the JUnit version to [5.13.4](https://docs.junit.org/current/release-notes/index.html#release-notes-5.13.4).

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Commit messages:
 - 7904070: Update to use JUnit 5.13.4

Changes: https://git.openjdk.org/jtreg/pull/282/files
  Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=282&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7904070
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jtreg/pull/282.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/282/head:pull/282

PR: https://git.openjdk.org/jtreg/pull/282