RFR: 8366575: Remove SDP support

[Jaikiran Pai]

On Tue, 28 Oct 2025 08:40:35 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

> Remove support for [SDP] (Sockets Direct Protocol), which has been obsolete for more than a decade – see [JDK-8366575] for details. Tier1-2 is clear.
> 
> [SDP]: https://docs.oracle.com/javase/tutorial/sdp/sockets/overview.html
> [JDK-8366575]: https://bugs.openjdk.org/browse/JDK-8366575

Hello Volkan, I'm not familiar with this protocol, but the clean up itself looks good to me.

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Marked as reviewed by jpai (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28012#pullrequestreview-3392545824