RFR: 7904136: JOL: JDK 25 compatibility fixes

[Aleksey Shipilev]

The umbrella issue for various JOL improvements for better JDK 25 support. Now that JDK 25 is finalized and stabilizing, we can rely on some details of JDK 25 implementation in JOL internals.

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Commit messages:
 - More test improvements
 - Pass tests on JDK 25
 - Layouter efficiency tests, hook up JDK 25 tests
 - Add Layouter to internals-estimates
 - Fix

Changes: https://git.openjdk.org/jol/pull/67/files
  Webrev: https://webrevs.openjdk.org/?repo=jol&pr=67&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7904136
  Stats: 351 lines in 9 files changed: 277 ins; 44 del; 30 mod
  Patch: https://git.openjdk.org/jol/pull/67.diff
  Fetch: git fetch https://git.openjdk.org/jol.git pull/67/head:pull/67

PR: https://git.openjdk.org/jol/pull/67