[vectorIntrinsics] RFR: 8263930: Add "VectorTest" implementation for Arm SVE

[Xiaohong Gong]

Currently the backend implementation for "VectorTestNode" is not added for Arm SVE. This node is used to test whether the mask vector is "allTrue/anyTrue". This patch adds the basic SVE implementation for it. Note that it is not totally based on the SVE predicate feature. And this will be improved once the basic SVE predicate feature is supported for Vector API.

For `"allTrue"`, a predicate will be firstly generated by comparing the mask vector with immediate "0". Then the result can be set based on whether no active elements are true. The codes look like:
  cmpeq   p0.s, p7/z, z17.s, #0   ; "z17.s" is the mask vector
  cset    w12, eq  // eq = none

For `"anyTrue"`, a predicate will be firstly generated by comparing the mask vector with immediate "-1". And the result can be set based on whether any active element is true. The codes look like:
  cmpeq   p0.s, p7/z, z17.s, #-1   ; "z17.s" is the mask vector
  cset    w12, ne  // ne = any

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Commit messages:
 - 8263930: Add "VectorTest" implementation for Arm SVE

Changes: https://git.openjdk.java.net/panama-vector/pull/52/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=52&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263930
  Stats: 142 lines in 2 files changed: 140 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/52.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/52/head:pull/52

PR: https://git.openjdk.java.net/panama-vector/pull/52