RFR: 8276: UI tests failing on Windows

[Marcus Hirt]

Ignoring failing tests for now.

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Commit messages:
 - Adding another ignore
 - 8276: Undoing PR #575
 - 8276: Requiring JDK 21+ for anything under application

Changes: https://git.openjdk.org/jmc/pull/594/files
  Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=594&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8276
  Stats: 113 lines in 109 files changed: 6 ins; 0 del; 107 mod
  Patch: https://git.openjdk.org/jmc/pull/594.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/594/head:pull/594

PR: https://git.openjdk.org/jmc/pull/594