[jdk21u-dev] RFR: 8351458: (ch) Move preClose to UnixDispatcher [v2]

[Shruthi Acharya]

> OpenJDK PR: https://github.com/openjdk/jdk/pull/23956
> OpenJDK bug: https://bugs.openjdk.org/browse/JDK-8351458
> 
> The original patch didn’t apply cleanly to the JDK21u-dev branch due to a copyright header mismatch. However, the rest of the changes were ported without issues. Manually updated the copyright header to resolve the conflict.

Shruthi Acharya has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  Backport 0de2cddf3a7be23f67af93972875af1235f3107e
  
  Signed-off-by: Shruthi <Shruthi.Shruthi1 at ibm.com>

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Changes:
  - all: https://git.openjdk.org/jdk21u-dev/pull/2051/files
  - new: https://git.openjdk.org/jdk21u-dev/pull/2051/files/d53a3cd5..57e506ff

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2051&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2051&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2051.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2051/head:pull/2051

PR: https://git.openjdk.org/jdk21u-dev/pull/2051