RFR: 8362123: ClassLoader Leak via Executors.newSingleThreadExecutor(...) [v2]

[Chris Dennis]

> Executors shutdown via `shutdownNow()` should have their cleanables cleaned to prevent a classloader leak. This can happen if a classloader exists that both references the wrapped executor and is referenced by the delegate executor.
> 
> To quote @Martin-Buchholz:
>> BTW: I find Cleaners much harder to use than old finalize, and it looks like I'm not the only one!

Chris Dennis has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  8362123: ClassLoader Leak via Executors.newSingleThreadExecutor(...)
  
  Executors shutdown via `shutdownNow()` should have their cleanables cleaned to
  prevent a classloader leak. This can happen if a classloader exists that both
  references the wrapped executor and is referenced by the delegate executor.

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Changes: https://git.openjdk.org/jdk/pull/26296/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26296&range=01
  Stats: 65 lines in 2 files changed: 63 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26296.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26296/head:pull/26296

PR: https://git.openjdk.org/jdk/pull/26296