[vectorIntrinsics+compress] RFR: 8274975: Add micro benchmark: ALIBABA selective store use case

[Joshua Zhu]

I separate my implementation of "compress" API into several patches for easy review.
This micro benchmark is extracted from the real use case inside in-memory databases: selectiveStore.
Test scenario: UseAVX=3; thread number = 8; conflict data percentage: 20% (that means 20% of mask bits are true)

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Commit messages:
 - 8274975: Add micro benchmark: ALIBABA selective store use case

Changes: https://git.openjdk.java.net/panama-vector/pull/149/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=149&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274975
  Stats: 189 lines in 1 file changed: 189 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/149.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/149/head:pull/149

PR: https://git.openjdk.java.net/panama-vector/pull/149