[jdk17u-dev] RFR: 8286872: Refactor add/modify notification icon (TrayIcon)

[Goetz Lindenmaier]

I backport this for parity with 17.0.6-oracle.

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Depends on: https://git.openjdk.org/jdk17u-dev/pull/866

Commit messages:
 - Backport 9f562ef7546c80e6ddce7b932f3f5ca17c741d21

Changes: https://git.openjdk.org/jdk17u-dev/pull/871/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=871&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286872
  Stats: 26 lines in 2 files changed: 14 ins; 5 del; 7 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/871.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/871/head:pull/871

PR: https://git.openjdk.org/jdk17u-dev/pull/871