[vectorIntrinsics+compress] RFR: 8274889: Intrinsify Vector.expand/compress APIs for X86 [v2]

[Jatin Bhateja]

> - Common C2 compiler entry point for compress/expand APIs.
> - Inline expansion handling and C2 graph creation.
> - For X86 current backed support is added for AVX512 which offers direct compress/expand instructions.
> 
> Patch has been co-contributed by  Joshua Zhu  (@Alibaba)

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

 - 8274889: Patch rebase with latest changes.
 - 8274889: Intrinsify Vector.expand/compress APIs for X86

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Changes: https://git.openjdk.java.net/panama-vector/pull/146/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=146&range=01
  Stats: 690 lines in 26 files changed: 448 ins; 152 del; 90 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/146.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/146/head:pull/146

PR: https://git.openjdk.java.net/panama-vector/pull/146