RFR: 8335181: Incorrect handling of HTTP/2 GOAWAY frames in HttpClient

[Jaikiran Pai]

Can I please get a review of this change which fixes the issue noted in https://bugs.openjdk.org/browse/JDK-8335181?

As noted in that issue, the current implementation in the `java.net.http.HttpClient` doesn't correctly handle an incoming GOAWAY frame. The HTTP3 RFC https://www.rfc-editor.org/rfc/rfc9113#name-goaway notes the specifics on what the expectations are when an endpoint receives a GOAWAY frame from the peer.

Before the changes proposed in this PR, the HttpClient implementation would (incorrectly) shutdown the connection and abort requests when a GOAWAY frame was received. The changes in this PR fixes that by retrying relevant unprocessed requests (if any) and not initiating any new streams on the connection.

A new test has been introduced to exercise this detail. The test continues to pass along with other existing tests. tier testing as well as a repeated testing (with test-repeat 50) is currently in progress with this change.

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Commit messages:
 - 8335181: Incorrect handling of HTTP/2 GOAWAY frames in HttpClient

Changes: https://git.openjdk.org/jdk/pull/20442/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20442&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335181
  Stats: 554 lines in 8 files changed: 518 ins; 0 del; 36 mod
  Patch: https://git.openjdk.org/jdk/pull/20442.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20442/head:pull/20442

PR: https://git.openjdk.org/jdk/pull/20442