RFR: 8355401: Remove unused HWperKB

[Stefan Karlsson]

I tiny cleanup to remove an unused constant. I saw this while looking at the surrounding code in another PR.

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Commit messages:
 - 8355401: Remove unused HWperKB

Changes: https://git.openjdk.org/jdk/pull/24827/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24827&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355401
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24827.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24827/head:pull/24827

PR: https://git.openjdk.org/jdk/pull/24827