RFR: 8362596: RISC-V: Improve _vectorizedHashCode intrinsic

[Fei Yang]

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).

Thanks!

-------------

Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26409#pullrequestreview-3037008439