RFR: 8290037: Bindings should clean up after themselves when their weak listeners go out of scope

Thu Jul 14 14:54:56 UTC 2022

This is an initial (incomplete) implementation of 8290037 for evaluation.

If the approach is agreed, I will modify the rest of the `*PropertyBase` classes which use weak listeners, and add some tests.

I didn't use `Cleaner` because cleaning up a listener may block.

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Commit messages:
 - Initial (incomplete) implementation for evaluation

Changes: https://git.openjdk.org/jfx/pull/827/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=827&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290037
  Stats: 192 lines in 4 files changed: 176 ins; 4 del; 12 mod
  Patch: https://git.openjdk.org/jfx/pull/827.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/827/head:pull/827

PR: https://git.openjdk.org/jfx/pull/827