[lworld] RFR: 8376532: [lworld] Size of BUFFERED layout is sometimes smaller than size of NULLABLE_NON_ATOMIC_FLAT layout

[Frederic Parain]

Fixes several bugs in the field layout builder, when the size and alignment constraint of the BUFFERED layout are adjusted to be compatible with all the other supported layouts.
The FieldLayoutAnalyzer framework has been updated to check this requirement each time a field layout log is processed.

Testing in progress.

Fred

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Commit messages:
 - Fix adjustements of BUFFERED layout

Changes: https://git.openjdk.org/valhalla/pull/1997/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1997&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376532
  Stats: 64 lines in 2 files changed: 40 ins; 0 del; 24 mod
  Patch: https://git.openjdk.org/valhalla/pull/1997.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1997/head:pull/1997

PR: https://git.openjdk.org/valhalla/pull/1997