RFR: 8349910: Implement JEP 517: HTTP/3 for the HTTP Client API [v5]

[Daniel Fuchs]

> Hi,
> 
> Please find here a PR for the implementation of [JEP 517: HTTP/3 for the HTTP Client API](https://openjdk.org/jeps/517).
> 
> The CSR can be viewed at [JDK-8350588: Implement JEP 517: HTTP/3 for the HTTP Client API](https://bugs.openjdk.org/browse/JDK-8350588)
> 
> This JEP proposes to enhance the HttpClient implementation to support HTTP/3.
> It adds a non-exposed / non-exported internal implementation of the QUIC protocol based on DatagramChannel and the SunJSSE SSLContext provider.

Daniel Fuchs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 422 commits:

 - merge latest changes from master branch
 - Undo whitespace change
 - Remove unnecessary import
 - Merge remote-tracking branch 'origin/master' into http3
 - Fix test license
 - Remove leftover file (test was moved to parent directory)
 - Remove unnecessary import
 - Update throws clauses
 - Merge remote-tracking branch 'origin/master' into http3
 - 8354275: Add HTTP/3 tests to `EmptyAuthenticate`
 - ... and 412 more: https://git.openjdk.org/jdk/compare/568dcc15...8c27f53c

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

Changes: https://git.openjdk.org/jdk/pull/24751/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24751&range=04
  Stats: 103018 lines in 469 files changed: 100164 ins; 1347 del; 1507 mod
  Patch: https://git.openjdk.org/jdk/pull/24751.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24751/head:pull/24751

PR: https://git.openjdk.org/jdk/pull/24751