RFR: 8275448: [REDO] AArch64: Implement string_compare intrinsic in SVE [v4]

[TatWai Chong]

> After JDK-8269559 was integrated there are failures in tier1 testing
> across Mac OS X 11.4 (aarch64) machines. Please see JDK-8275263.
> 
> This patch is NOT functional; rather, this tends to verify potential
> toolchain issues as the original patch pass testing on other
> platforms.
> 
> In this patch, we remove new SVE-related matching rules and register
> class introduced in the original patch to minimally affect the
> non-SVE part.

TatWai Chong has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:

 - Merge master
 - Add the matching rule in td file, enable control path in the code stub.
 - Add the register class and description for this SVE intrinsic.
 - 8275448: [REDO] AArch64: Implement string_compare intrinsic in SVE
   
   After JDK-8269559 was integrated there are failures in tier1 testing
   across Mac OS X 11.4 (aarch64) machines. Please see JDK-8275263.
   
   This patch isn't functional; rather, this tends to verify potential
   toolchain issues as the original patch passes testing on other
   platforms.
   
   In this patch, we remove new SVE-related matching rules and register
   class introduced in the original patch to minimally affect the
   non-SVE part.

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

Changes: https://git.openjdk.java.net/jdk/pull/6072/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6072&range=03
  Stats: 423 lines in 9 files changed: 412 ins; 0 del; 11 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6072.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6072/head:pull/6072

PR: https://git.openjdk.java.net/jdk/pull/6072