[lworld] RFR: 8377736: [lworld] Enable EliminateAutoBox when preview is disabled

[Tobias Hartmann]

Due to [JDK-8328675](https://bugs.openjdk.org/browse/JDK-8328675), `EliminateAutoBox` is currently disabled in Valhalla but we should enable it when preview features are disabled.

Thanks,
Tobias

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Commit messages:
 - 8377736: [lworld] Enable EliminateAutoBox when preview is disabled

Changes: https://git.openjdk.org/valhalla/pull/2086/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2086&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8377736
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/2086.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2086/head:pull/2086

PR: https://git.openjdk.org/valhalla/pull/2086