RFR: 8284855: Update needed to Cleaners added to jdk.crypto.cryptoki

[Xue-Lei Andrew Fan]

This is an effort to fix a problem introduced in the fix for [JDK-8284368](https://bugs.openjdk.java.net/browse/JDK-8284368), which replaced the finalizers in jdk.crypto.cryptoki with Cleaners.  However, there is a problem with the code changes. The Runnables registered with Cleaner refer to the object being registered ('this'). Meaning, the Cleaner mechanism will keep the objects reachable, preventing them from being cleaned and collected.

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Commit messages:
 - 8284855: Update needed to Cleaners added to jdk.crypto.cryptoki

Changes: https://git.openjdk.java.net/jdk/pull/8248/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8248&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284855
  Stats: 46 lines in 6 files changed: 10 ins; 21 del; 15 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8248.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8248/head:pull/8248

PR: https://git.openjdk.java.net/jdk/pull/8248