[jdk21u-dev] RFR: 8341378: Open source few TrayIcon tests - Set8

[Goetz Lindenmaier]

I backport this for parity with 21.0.8-oracle

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Commit messages:
 - backport b9db74a64577bf2b79570a789c91de6549a50788

Changes: https://git.openjdk.org/jdk21u-dev/pull/1581/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1581&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8341378
  Stats: 614 lines in 2 files changed: 614 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1581.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1581/head:pull/1581

PR: https://git.openjdk.org/jdk21u-dev/pull/1581