[jfx21u] RFR: 8318841: macOS: Memory leak with MenuItem when Menu.useSystemMenuBar(true) is used

[Johan Vos]

8318841: macOS: Memory leak with MenuItem when Menu.useSystemMenuBar(true) is used

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Commit messages:
 - Backport 8dd3c37cae3dd52dc3a258033d0e8f168ceaf307

Changes: https://git.openjdk.org/jfx21u/pull/65/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx21u&pr=65&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318841
  Stats: 80 lines in 4 files changed: 80 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx21u/pull/65.diff
  Fetch: git fetch https://git.openjdk.org/jfx21u.git pull/65/head:pull/65

PR: https://git.openjdk.org/jfx21u/pull/65