RFR: 8310459: [BACKOUT] 8304450: [vectorapi] Refactor VectorShuffle implementation

[Sandhya Viswanathan]

On Fri, 23 Jun 2023 16:43:32 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

> Backing out shuffle related overhaul done with [JDK-8304450](https://bugs.openjdk.org/browse/JDK-8304450), we saw significant performance degradation in VectorAPI JMH micros and some of our internal benchmarks. Following two issues were filed on this recently.
> 
> 1/ [JDK-8310459](https://bugs.openjdk.org/browse/JDK-8310459): Performance drop in VectorAPI slice / unslice performance w.r.t to JDK-20.
> 2/ [JDK-8309373](https://bugs.openjdk.org/browse/JDK-8309373): Performance drop in Vector-API based kernel with JDK-21.
> 
> A follow-up JBS [JDK-8310691](https://bugs.openjdk.org/browse/JDK-8310691) is created to address this in JDK-22.
> 
> Best Regards,
> Jatin

Marked as reviewed by sviswanathan (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/14629#pullrequestreview-1499048603