RFR: 8288294: [vector] Add Identity/Ideal transformations for vector logic operations [v2]

[Xiaohong Gong]

> This patch adds the following transformations for vector logic operations such as "`AndV, OrV, XorV`", incuding:
> 
>   (AndV v (Replicate m1))   => v
>   (AndV v (Replicate zero)) => Replicate zero
>   (AndV v v)                => v
> 
>   (OrV v (Replicate m1))    => Replicate m1
>   (OrV v (Replicate zero))  => v
>   (OrV v v)                 => v
> 
>   (XorV v v)                => Replicate zero
> 
> where "`m1`" is the integer constant -1, together with the same optimizations for vector mask operations like "`AndVMask, OrVMask, XorVMask`".

Xiaohong Gong has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - Merge branch 'jdk:master' into JDK-8288294
 - 8288294: [vector] Add Identity/Ideal transformations for vector logic operations

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Changes: https://git.openjdk.org/jdk/pull/9211/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9211&range=01
  Stats: 639 lines in 4 files changed: 629 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/9211.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9211/head:pull/9211

PR: https://git.openjdk.org/jdk/pull/9211