RFR: 8369595: HttpClient: HttpHeaders.firstValueAsLong failures should be converted to ProtocolException [v5]

[Daniel Jeliński]

On Wed, 26 Nov 2025 10:39:20 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

>> Add guards against `HttpHeaders::firstValueAsLong` failures. `H3MalformedResponseTest` is overhauled – migrated to JUnit, reinforced with exception type tests, etc. – but not all `firstValueAsLong` changes are verified with new additional tests. `test/jdk/java/net/httpclient/` tests still do pass.
>
> Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Introduce dangling `firstValueAsLong("content-length")` calls back

Marked as reviewed by djelinski (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/28431#pullrequestreview-3523860341