RFR: 8358594: Misleading keyLength value captured in JFR event for ML-KEM key [v2]

[Weijun Wang]

> Add more comment on why `KeyUtil::getKeySize` could return -1. Add a new method `getNistCategory` to get the NIST security category.

Weijun Wang has updated the pull request incrementally with one additional commit since the last revision:

  addressing Mark's comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25642/files
  - new: https://git.openjdk.org/jdk/pull/25642/files/bd7abe8e..157c53b9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25642&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25642&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/25642.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25642/head:pull/25642

PR: https://git.openjdk.org/jdk/pull/25642