[vectorIntrinsics] RFR: 8253585: Add basic vector mask implementation for Arm SVE [v3]

[Xiaohong Gong]

> Summary: Add the SVE match rule support for vector mask ops.
> 
> ======
> 
> Currently the vector mask related operations like vector mask load/store, vector mask compare and vector blend are not supported for Arm SVE. This patch adds the basic backend implementation for them.
> 
> BTW, this is a basic version for vector mask operations that does not use the SVE predicate features. And we will make it happen in future.

Xiaohong Gong has updated the pull request incrementally with one additional commit since the last revision:

  Adjust the match rule costs

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Changes:
  - all: https://git.openjdk.java.net/panama-vector/pull/20/files
  - new: https://git.openjdk.java.net/panama-vector/pull/20/files/ec639ba7..ad4f8c36

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=20&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=20&range=01-02

  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/20.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/20/head:pull/20

PR: https://git.openjdk.java.net/panama-vector/pull/20