RFR: 8371471: HttpClient: Log HTTP/3 handshake failures if logging errors is enabled [v3]

[Daniel Fuchs]

> Surprisingly if the QUIC handshake fails exceptionally, and `-Djdk.httpclient.HttpClient.log=errors` is specified, the exception is not logged. This change fixes that.

Daniel Fuchs has updated the pull request incrementally with one additional commit since the last revision:

  Review feedback

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28196/files
  - new: https://git.openjdk.org/jdk/pull/28196/files/238904e4..ff71b9e1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28196&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28196&range=01-02

  Stats: 16 lines in 2 files changed: 6 ins; 6 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/28196.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28196/head:pull/28196

PR: https://git.openjdk.org/jdk/pull/28196