[lworld] RFR: 8374554: [lworld] Field layout assert with UseCompactObjectHeaders

[Frederic Parain]

Fix an issue in the logic processing the beginning of a field layout, abstract value class with fields were processing correctly.

Add more configurations to tests in order to cover compact object headers too.
Re-enabled some tests that were disabled, an extended them to cover compact object headers too.

Tested with Mach5 tier 1 to 3.

Thank you,

Fred

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

Commit messages:
 - Fix generation of layout beginning

Changes: https://git.openjdk.org/valhalla/pull/1862/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1862&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374554
  Stats: 243 lines in 5 files changed: 179 ins; 23 del; 41 mod
  Patch: https://git.openjdk.org/valhalla/pull/1862.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1862/head:pull/1862

PR: https://git.openjdk.org/valhalla/pull/1862