RFR: 8362596: RISC-V: Improve _vectorizedHashCode intrinsic

[duke]

On Mon, 21 Jul 2025 08:07:48 GMT, Yuri Gaevsky <duke at openjdk.org> wrote:

> This is a micro-optimization for RISC-V SpacemiT K1 CPU to fix [encountered performance regression](https://github.com/openjdk/jdk/pull/17413#issuecomment-3082664335).

@ygaevsky 
Your change (at version 1d5cb89486b935e2f30365f66e6bf5afd2058424) is now ready to be sponsored by a Committer.

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PR Comment: https://git.openjdk.org/jdk/pull/26409#issuecomment-3124451738