[jdk17u-dev] RFR: 7026262: HttpServer: improve handling of finished HTTP exchanges

[Christoph Langer]

Hi all,

This pull request contains a backport of [JDK-7026262](https://bugs.openjdk.org/browse/JDK-7026262), commit [a5ffa079](https://github.com/openjdk/jdk21u-dev/commit/a5ffa079a0d6107be652bc026f5c91b7dcd791f8) from the [openjdk/jdk21u-dev](https://git.openjdk.org/jdk21u-dev) repository.

The commit being backported was authored by Daniel Jeliński on 27 Mar 2023 and was reviewed by Daniel Fuchs and Michael McMahon.

Thanks!

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Commit messages:
 - Backport a5ffa079a0d6107be652bc026f5c91b7dcd791f8

Changes: https://git.openjdk.org/jdk17u-dev/pull/2782/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=2782&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-7026262
  Stats: 325 lines in 9 files changed: 288 ins; 19 del; 18 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/2782.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/2782/head:pull/2782

PR: https://git.openjdk.org/jdk17u-dev/pull/2782