RFR: 8324643: [lworld] remove ACC_VALUE flag and the 'identity' modifier

[Vicente Romero]

removing flag ACC_VALUE and identity modifier and related refactorings

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Commit messages:
 - 8324643: [lworld] remove ACC_VALUE flag and the 'identity' modifier

Changes: https://git.openjdk.org/valhalla/pull/977/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=977&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324643
  Stats: 687 lines in 41 files changed: 21 ins; 481 del; 185 mod
  Patch: https://git.openjdk.org/valhalla/pull/977.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/977/head:pull/977

PR: https://git.openjdk.org/valhalla/pull/977