RFR: 8312306: Add more Reference.reachabilityFence() calls to the security classes using Cleaner

Tue Aug 22 18:29:47 UTC 2023

This PR updates the various security classes using Cleaner with the try/finally pattern. Also noticed that SunJCE's PBEKey impl class overrides the destroy() method but not the isDestroyed() method, fixed this inconsistency as well.

Thanks in advance for the review!

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Commit messages:
 - minor comments update
 - 8312306: Add more Reference.reachabilityFence() calls to the security classes using Cleaner

Changes: https://git.openjdk.org/jdk/pull/15390/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15390&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312306
  Stats: 238 lines in 6 files changed: 149 ins; 4 del; 85 mod
  Patch: https://git.openjdk.org/jdk/pull/15390.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15390/head:pull/15390

PR: https://git.openjdk.org/jdk/pull/15390