[lworld] RFR: 8326429: [lworld] Java language implementation of value classes and objects, phase 1

[Vicente Romero]

This PR is a first phase of the implementation of [1] and thus of [2]. The code in this PR should unblock other teams waiting on javac support for JEP 401.

TIA

[1] https://bugs.openjdk.org/browse/JDK-8317277
[2] https://cr.openjdk.org/~dlsmith/jep401/jep401-20240131/specs/value-objects-jls.html

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Commit messages:
 - 8326429: [lworld] Java language implementation of value classes and objects, phase 1

Changes: https://git.openjdk.org/valhalla/pull/1015/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1015&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8326429
  Stats: 14752 lines in 300 files changed: 2779 ins; 11181 del; 792 mod
  Patch: https://git.openjdk.org/valhalla/pull/1015.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1015/head:pull/1015

PR: https://git.openjdk.org/valhalla/pull/1015