RFR: 8334599: Improve code from JDK-8302671

[Phil Race]

On Thu, 20 Jun 2024 08:29:39 GMT, Julian Waters <jwaters at openjdk.org> wrote:

> In [JDK-8302671](https://bugs.openjdk.org/browse/JDK-8302671) I fixed a memmove decay bug by rewriting a sizeof on an array to an explicit size of 256, but this is a bit of a band aid fix. It's come to my attention that in C++, one can pass an array by reference, which causes sizeof to work correctly on an array and has the added bonus of enforcing an array of that size on the arguments passed to that method. I've reverted my change from 8302671 and instead explicitly made kstate an array reference so that sizeof works on the array as expected, and that the array size can be explicitly set in the array brackets
> 
> Verification: https://godbolt.org/z/Ezj76eWWY and GitHub Actions

Harmless, I hope, but it doesn't change that 256 is hard-coded in multiple places AND that the caller has to get it right too .. if the caller passes a shorter array things can still go wrong.
Why can't we EVERYWHERE use the definition used to create the array passed in
        KB_STATE_SIZE = 256
instead of a mixture.

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PR Review: https://git.openjdk.org/jdk/pull/19798#pullrequestreview-2131336310