[vectorIntrinsics] RFR: Merge panama-vector:master [v2]

[Ningsheng Jian]

> Another clean merge. Verified on aarch64 and x86.

Ningsheng Jian has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 737 commits:

 - Merge jdk/master into vectorIntrinsics
 - Merge panama-vector:master
   
   Reviewed-by: jbhateja, psandoz
 - 8263532: C2: Improve vector box elimination for Phi nodes
   
   Reviewed-by: psandoz
 - Merge panama-vector:master
   
   Co-authored-by: Ningsheng Jian <njian at openjdk.org>
 - Optimize mem barriers for ByteBuffer cases
   
   Reviewed-by: psandoz, vlivanov
 - 8271009: AArch64: Wrap duplicated SVE instructions into a single method
   
   Reviewed-by: njian, xgong
 - 8271005: AArch64: Add SVE codegen for VectorMask reduction nodes
   
   Reviewed-by: njian, eliu
 - Merge panama-vector:master
   
   Reviewed-by: xgong, sviswanathan
 - 8269264: Some more cleanups for Vector API SVE support
   
   Reviewed-by: xgong
 - Merge panama-vector:master
   
   Co-authored-by: Ningsheng Jian <njian at openjdk.org>
 - ... and 727 more: https://git.openjdk.java.net/panama-vector/compare/54b45676...3022e376

-------------

Changes: https://git.openjdk.java.net/panama-vector/pull/127/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=127&range=01
  Stats: 73376 lines in 122 files changed: 72140 ins; 213 del; 1023 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/127.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/127/head:pull/127

PR: https://git.openjdk.java.net/panama-vector/pull/127