RFR: 8376434: Remove AppContext from awt ImageFetcher implementation

[Phil Race]

Remove AppContext from ImageFetcher

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Commit messages:
 - 8376434

Changes: https://git.openjdk.org/jdk/pull/29441/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29441&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376434
  Stats: 45 lines in 1 file changed: 2 ins; 27 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/29441.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29441/head:pull/29441

PR: https://git.openjdk.org/jdk/pull/29441