RFR: 8314755: Resource leak: SwingWorker listener keeps strong reference to executor [v2]

[Christopher Sahnwaldt]

> In https://github.com/openjdk/jdk/commit/b8af3d50192f8bc98d83f8102f0fd1989f302e32 the weak reference was accidentally changed from a field to a local variable, which means that the PropertyChangeListener keeps a strong reference to executorService, which is a resource leak

Christopher Sahnwaldt has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'openjdk:master' into patch-1
 - SwingWorker.java: appContext shouldn't keep a strong reference to executorService
   
   In https://github.com/openjdk/jdk/commit/b8af3d50192f8bc98d83f8102f0fd1989f302e32 the weak reference was accidentally changed from a field to a local variable, which means that the PropertyChangeListener keeps a strong reference to executorService, which is a resource leak

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15081/files
  - new: https://git.openjdk.org/jdk/pull/15081/files/59d7bd5d..f11dc305

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15081&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15081&range=00-01

  Stats: 75083 lines in 2378 files changed: 43178 ins; 16345 del; 15560 mod
  Patch: https://git.openjdk.org/jdk/pull/15081.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15081/head:pull/15081

PR: https://git.openjdk.org/jdk/pull/15081