RFR: 8294194: [AArch64] Create intrinsics compress and expand [v2]

[Eric Liu]

On Tue, 1 Nov 2022 09:49:06 GMT, Stuart Monteith <smonteith at openjdk.org> wrote:

>> We don't want to enable this on detection of the feature - if UseSVE is disable, we'll be missing the SVE infrastructure that we are dependent on in the compiler.
>
> Correction - we don't want to enable this solely on the present of the feature. With -XX:-UseSVE on the command line, this would break, so we need UseSVE and the feature to be present.

My understanding: 
`VM_Version::supports_svebitperm()` means if the hardware supports the feature or not. `UseSVE` means if user wants to use SVE(2).

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PR: https://git.openjdk.org/jdk/pull/10537