RFR: 8316325: [lw5] sync javac with the current JVMS, particularly assertions on new class attributes [v3]

[Vicente Romero]

> This PR is implementing assertions on new classfile attributes, see [1]
> 
> [1] https://cr.openjdk.org/~dlsmith/jep401/jep401-20230519/specs/flattened-heap-jvms.html

Vicente Romero has updated the pull request incrementally with one additional commit since the last revision:

  minor refactoring

-------------

Changes:
  - all: https://git.openjdk.org/valhalla/pull/927/files
  - new: https://git.openjdk.org/valhalla/pull/927/files/a29389be..cdf0e82e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=927&range=02
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=927&range=01-02

  Stats: 12 lines in 8 files changed: 3 ins; 3 del; 6 mod
  Patch: https://git.openjdk.org/valhalla/pull/927.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/927/head:pull/927

PR: https://git.openjdk.org/valhalla/pull/927