[vectorIntrinsics] RFR: 8283598: [vectorapi] Add new vector operation for compress and expand bits [v3]

[Smita Kamath]

> Hi,
> 
> I've added support for new vector operations for compressing bits of integral vector types(Byte/Short/Integer/Long).
> The implementation is based on Compress or Generalized Extract mentioned in Hackers Delight by Henry S. Warren, Jr.
> The implementation does the following: given a mask and the number to be compressed, the bits of the number corresponding to the set mask bit are selected and compressed. 
> 
> Currently, this PR addresses only Java changes for compress bits operation. I've also updated the test framework.
> Do review and share feedback.

Smita Kamath has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge vectorIntrinsics
 - 1) Removed compress bits implementation for byte and short
   2) Added expand bits operation for int and long 3) Addressed review comments about code style 4) updated tests
 - Compress bits implementation for byte/short/int/long

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Changes: https://git.openjdk.java.net/panama-vector/pull/184/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=184&range=02
  Stats: 18381 lines in 83 files changed: 18376 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/184.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/184/head:pull/184

PR: https://git.openjdk.java.net/panama-vector/pull/184