[lworld] RFR: 8364095: [lworld] AccessFlags location and release need futher work for Valhalla (IDENTITY and SUPER)

[Chen Liang]

Improve access flag reflection for preview on/off.

In this process, I noted javac is incorrectly injecting ACC_IDENTITY to 69.0 class' `InnerClasses` attribute and fixed that.

There is still some inconsistency, such as implying ACC_IDENTITY when preview is on for classes. Don't know if we have discussed on this yet.

No new test failures.

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Commit messages:
 - Stage
 - Stage
 - Trivial
 - Unit test
 - Fix identity flag missing for preview inner classes
 - Stage
 - Fixes
 - Make use of current preview features

Changes: https://git.openjdk.org/valhalla/pull/1533/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1533&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364095
  Stats: 336 lines in 43 files changed: 189 ins; 81 del; 66 mod
  Patch: https://git.openjdk.org/valhalla/pull/1533.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1533/head:pull/1533

PR: https://git.openjdk.org/valhalla/pull/1533