RFR: 8291600: [vectorapi] vector cast op check is not always needed for vector mask cast [v7]

[Xiaohong Gong]

On Thu, 15 Sep 2022 07:59:22 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Yes, you are right. That's also what is the first version of this PR (please see: https://openjdk.github.io/cr/?repo=jdk&pr=9737&range=00).  And since @merykitty  suggested to unify the whole vector mask cast operations with `VectorMaskCastNode`, I prepare a follow-up patch to specifically do this refactorization (please see: https://github.com/openjdk/jdk/pull/10192). And as suggested by @DamonFool , we only fix the `FIRST_NONZERO` performance issue in this PR.
>
> Yes, I just noticed that #10192 is addressing above two comments

Yeah, thanks so much for looking at that PR as well!

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PR: https://git.openjdk.org/jdk/pull/9737