RFR: 8358594: Misleading keyLength value captured in JFR event for ML-KEM key [v3]

[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:

  enhance test to be exhaustive

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25642/files
  - new: https://git.openjdk.org/jdk/pull/25642/files/157c53b9..5ec95fb2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25642&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25642&range=01-02

  Stats: 42 lines in 1 file changed: 25 ins; 8 del; 9 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