[vectorIntrinsics+compress] RFR: 8274837: Intel backend support for compress VectorAPI [v2]

[Joshua Zhu]

> I separate my implementation of "compress" API into several patches for easy review.
> This patch is the change in backend used to support vector-to-vector compress API.
> ByteVector and ShortVector are supported in AVX512vbmi2.

Joshua Zhu has updated the pull request incrementally with one additional commit since the last revision:

  update

-------------

Changes:
  - all: https://git.openjdk.java.net/panama-vector/pull/144/files
  - new: https://git.openjdk.java.net/panama-vector/pull/144/files/3d7cdeb7..ae48fca8

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=144&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=144&range=00-01

  Stats: 49 lines in 5 files changed: 41 ins; 6 del; 2 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/144.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/144/head:pull/144

PR: https://git.openjdk.java.net/panama-vector/pull/144