RFR: 8362151: Remove unnecessary ClassLoaderDataGraph friend classes

[Thomas Schatzl]

Hi all,

  please review this trivial removal of some obsolete code related to friend declarations of deleted classes.

Testing: gha

Thanks,
  Thomas

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Commit messages:
 - 8362151

Changes: https://git.openjdk.org/jdk/pull/26290/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26290&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8362151
  Stats: 6 lines in 2 files changed: 0 ins; 6 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26290.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26290/head:pull/26290

PR: https://git.openjdk.org/jdk/pull/26290