[lworld] RFR: 8366668: [lworld] Follow-up work from the array metadata re-work

[Tobias Hartmann]

This is a follow-up from [JDK-8366705](https://bugs.openjdk.org/browse/JDK-8366705) resolving a large number of ToDos in the implementation and tests.

There are a few remaining ToDos that I'll address with [JDK-8370341](https://bugs.openjdk.org/browse/JDK-8370341) because this change is getting too large and is blocking other work.

Best regards,
Tobias

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Commit messages:
 - Remaining ToDos
 - v14
 - Merge
 - v13
 - v12
 - Merge branch 'lworld' into JDK-8366668
 - v11
 - v10
 - Fred's review comments
 - v9
 - ... and 9 more: https://git.openjdk.org/valhalla/compare/3af03b2e...a62f3890

Changes: https://git.openjdk.org/valhalla/pull/1672/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1672&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8366668
  Stats: 915 lines in 45 files changed: 637 ins; 135 del; 143 mod
  Patch: https://git.openjdk.org/valhalla/pull/1672.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1672/head:pull/1672

PR: https://git.openjdk.org/valhalla/pull/1672