[lilliput-jdk21u:lilliput] RFR: 8316126: [Lilliput/JDK21] Cherry-pick: 8305895: Implementation: JEP 450: Compact Object Headers (Experimental)

[Roman Kennke]

Let's cherry-pick the current state of upstream https://github.com/openjdk/jdk/pull/13961 into Lilliput/JDK21u.

Testing:
 - [ ] tier1 +UCOH
 - [ ] tier1 -UCOH

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Commit messages:
 - 8316126: [Lilliput/JDK21] Cherry-pick: 8305895: Implementation: JEP 450: Compact Object Headers (Experimental)

Changes: https://git.openjdk.org/lilliput-jdk21u/pull/5/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput-jdk21u&pr=5&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316126
  Stats: 1255 lines in 110 files changed: 935 ins; 115 del; 205 mod
  Patch: https://git.openjdk.org/lilliput-jdk21u/pull/5.diff
  Fetch: git fetch https://git.openjdk.org/lilliput-jdk21u.git pull/5/head:pull/5

PR: https://git.openjdk.org/lilliput-jdk21u/pull/5