[lworld] RFR: 8371915: [lworld] LayoutKind enum should have helper methods [v2]

[Frederic Parain]

> Add some helper methods to test properties of layouts in a more reliable way.
> 
> Tested with Mach5, tier 1 to 3.
> 
> Fred

Frederic Parain has updated the pull request incrementally with one additional commit since the last revision:

  Fix ArrayProperties for NULLABLE_ATOMIC_FLAT

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/1745/files
  - new: https://git.openjdk.org/valhalla/pull/1745/files/f10829c3..bb659fc9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1745&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1745&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/valhalla/pull/1745.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1745/head:pull/1745

PR: https://git.openjdk.org/valhalla/pull/1745