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

[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)

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Commit messages:
 - 8274889: Intrinsify Vector.expand/compress APIs for X86

Changes: https://git.openjdk.java.net/panama-vector/pull/146/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=146&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274889
  Stats: 821 lines in 26 files changed: 606 ins; 127 del; 88 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