RFR: 8361532: RISC-V: Several vector tests fail after JDK-8354383

[Gui Cao]

On Tue, 8 Jul 2025 02:30:27 GMT, Dingli Zhang <dzhang at openjdk.org> wrote:

> Hi all,
> Please take a look and review this PR, thanks!
> 
> After [JDK-8354383](https://bugs.openjdk.org/browse/JDK-8354383) , several test cases fail when fastdebug with RVV.
> The reason for the error is that riscv lacks CastVV with dst as the mask register. 
> This PR adds the corresponding matching rules.
> 
> ### Testing
> qemu-system with RVV:
> * [x]  Run jdk_vector (fastdebug)
> * [x]  Run compiler/vectorapi (fastdebug)

Marked as reviewed by gcao (Author).

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PR Review: https://git.openjdk.org/jdk/pull/26178#pullrequestreview-2999838017