[jdk21u-dev] RFR: 8332641: Update nsk.share.jpda.Jdb to don't use finalization

[Goetz Lindenmaier]

I backport this for parity with 21.0.8-oracle

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Commit messages:
 - Backport f66a58661459bf64212ec332540c12d5d691270f

Changes: https://git.openjdk.org/jdk21u-dev/pull/1688/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1688&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332641
  Stats: 25 lines in 2 files changed: 8 ins; 7 del; 10 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1688.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1688/head:pull/1688

PR: https://git.openjdk.org/jdk21u-dev/pull/1688