RFR: 8367976: Validate and clamp jdk.httpclient.bufsize [v4]

[Volkan Yazici]

> Validate and clamp the value populated from the `jdk.httpclient.bufsize` system property. Added two new tests: Does clamping work? Does the minimum value wedge the client?

Volkan Yazici 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 five additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into bufSizeClamp
 - Switch to POST and repeated-request in `BufferSize1Test`
 - Apply property doc suggestion
   
   Co-authored-by: Daniel Fuchs <67001856+dfuch at users.noreply.github.com>
 - Update `module-info.java` docs
 - Clamp `Utils::BUFSIZE`

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27874/files
  - new: https://git.openjdk.org/jdk/pull/27874/files/0cd7deef..26fdcb4a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27874&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27874&range=02-03

  Stats: 6032 lines in 184 files changed: 3763 ins; 1095 del; 1174 mod
  Patch: https://git.openjdk.org/jdk/pull/27874.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27874/head:pull/27874

PR: https://git.openjdk.org/jdk/pull/27874