RFR: 8368966: Remove spurious VMStructs friends

Tue Sep 30 16:42:35 UTC 2025

In this PR I propose a small clean up to remove several spurious friends of `VMStructs`. I could not find any reference to them in `vmStructs*`, or private symbols are not mentioned so the friendship can be removed.

Passes tier1 and tier2 (fastdebug).

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Commit messages:
 - Merge branch 'master' into cleanup-vmstructs
 - nn

Changes: https://git.openjdk.org/jdk/pull/27583/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27583&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368966
  Stats: 80 lines in 47 files changed: 1 ins; 78 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27583.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27583/head:pull/27583

PR: https://git.openjdk.org/jdk/pull/27583