RFR: 8309601: [JVMCI] AMD64#getLargestStorableKind returns incorrect mask kind

[Tom Rodriguez]

On Tue, 13 Jun 2023 08:24:23 GMT, Gergö Barany <gbarany at openjdk.org> wrote:

> `jdk.vm.ci.amd64.AMD64#getLargestStorableKind(RegisterCategory)` unconditionally returns `AMD64Kind.MASK64` for mask registers. This is only correct if the target supports AVX512BW. On other AVX512 versions this should be `MASK16`.
> 
> The Graal compiler uses this method to determine how to spill a given register. An incorrect size will lead to compilation errors due to trying to emit a move with a size that is not supported by the target. I have manually verified that this fixes those problems.

Looks good

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Marked as reviewed by never (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/14441#pullrequestreview-1484020268