RFR: 7903821: Update jtreg to bundle JUnit 5.11.0

[Christian Stein]

Please review this change to bundle [JUnit 5.11.0](https://junit.org/junit5/docs/current/release-notes/index.html#release-notes-5.11.0) with the upcoming [jtreg 7.5](https://bugs.openjdk.org/browse/JDK-8339238).

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Commit messages:
 - 7903821: Update jtreg to bundle JUnit 5.11.0

Changes: https://git.openjdk.org/jtreg/pull/227/files
  Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=227&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903821
  Stats: 4 lines in 2 files changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jtreg/pull/227.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/227/head:pull/227

PR: https://git.openjdk.org/jtreg/pull/227