RFR: 8368249: HttpClient: Translate exceptions thrown by sendAsync [v7]

[Volkan Yazici]

> Ensure `HttpClient::sendAsync` translates every operational failure to an `IOException` as per specification.
> 
> `tier1-2` passes with the proposed changes.
> 
> **Context:** The parent issue, [JDK-8364733], reports that `HttpClient::sendAsync` leaks exceptions which do not extend from `IOException`, and this violates the method's specification. The [JDK-8367067] (#26876) sub-task improved issues around exceptions thrown by request body publishers – which triggered the first encounter with this problem. This PR (and its associated sub-task) is aimed to end this saga.
> 
> [JDK-8364733]: https://bugs.openjdk.org/browse/JDK-8364733
> [JDK-8367067]: https://bugs.openjdk.org/browse/JDK-8367067

Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:

  Revert unnecessary changes to `AbstractThrowingSubscribers`

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27787/files
  - new: https://git.openjdk.org/jdk/pull/27787/files/5621d911..6fad4020

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27787&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27787&range=05-06

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/27787.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27787/head:pull/27787

PR: https://git.openjdk.org/jdk/pull/27787