[jdk21u-dev] RFR: 8347596: Update HSS/LMS public key encoding

[Paul Hohensee]

Backport for parity with Oracle 21.0.8. Clean except the hunk for KeyUtil.java applies to code that doesn't exist in 21u.

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Commit messages:
 - Merge branch 'master' into 8347596
 - Backport 0ee6ba9c4c998baeb733363d00db138864f49406

Changes: https://git.openjdk.org/jdk21u-dev/pull/1719/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1719&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347596
  Stats: 41 lines in 2 files changed: 19 ins; 10 del; 12 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1719.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1719/head:pull/1719

PR: https://git.openjdk.org/jdk21u-dev/pull/1719