RFR: 8349509: [macos] Clean up macOS dead code in jpackage

[Alexander Matveev]

- Removed unused `INSTALLER_SUFFIX` bundler param.
- Removed unreachable if branch in `MacAppImageBuilder`.

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Commit messages:
 - 8349509: [macos] Clean up macOS dead code in jpackage

Changes: https://git.openjdk.org/jdk/pull/23504/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23504&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349509
  Stats: 27 lines in 3 files changed: 1 ins; 20 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/23504.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23504/head:pull/23504

PR: https://git.openjdk.org/jdk/pull/23504