[vectorIntrinsics] RFR: Improve mask reduction operations on AVX

[Jatin Bhateja]

On Tue, 2 Nov 2021 16:36:47 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

> > Besides, I found out that C2 fails with `Long128Vector`, even a simple operation of `LONG_128_1.eq(LONG_128_2)`, is this a known behaviour?
> 
> I was not aware of that, @jatin-bhateja might know more.

Yes, this the current [behavior ](https://github.com/openjdk/panama-vector/pull/157#discussion_r738549758)

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PR: https://git.openjdk.java.net/panama-vector/pull/158