RFR: 8376992: Remove AppContext from SystemTray implementation [v4]

[Phil Race]

> Remove AppContext from java/awt/SystemTray

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

  8376992

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29531/files
  - new: https://git.openjdk.org/jdk/pull/29531/files/bdc42357..e40cde2a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29531&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29531&range=02-03

  Stats: 9 lines in 1 file changed: 0 ins; 7 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/29531.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29531/head:pull/29531

PR: https://git.openjdk.org/jdk/pull/29531