[vectorIntrinsics] RFR: 8283145: [vector] Add the compiler IR and aarch64 support for count leading and trailing zeros [v2]

[Xiaohong Gong]

> This patch adds the hotspot compiler implementations for the vector operations of count leading and trailing zeros. It adds:
>  - two vector nodes respectively for the two vector operations
>  - the backend implementations for aarch64 NEON and SVE

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

  Address review comments in the aarch64 ad files

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Changes:
  - all: https://git.openjdk.java.net/panama-vector/pull/180/files
  - new: https://git.openjdk.java.net/panama-vector/pull/180/files/2be0472c..39e51053

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=180&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=180&range=00-01

  Stats: 97 lines in 4 files changed: 12 ins; 25 del; 60 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/180.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/180/head:pull/180

PR: https://git.openjdk.java.net/panama-vector/pull/180