[jdk17u-dev] RFR: 8268231: Aarch64: Use Ldp in intrinsics for String.compareTo

[Dmitry Chuyko]

Original patch applies cleanly.

Benchmark results of test/micro/org/openjdk/bench/java/lang/StringCompareToDifferentLength.java correspond to original issue, 10-25% 17u improvements on Graviton 2 for long enough strings (72+ chars).

Testing: tier1, tier2 (aarch64).

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Commit messages:
 - Backport 6d1d4d52928ed38bbc73ddcbede5389995a8e65f

Changes: https://git.openjdk.java.net/jdk17u-dev/pull/91/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17u-dev&pr=91&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268231
  Stats: 106 lines in 1 file changed: 39 ins; 40 del; 27 mod
  Patch: https://git.openjdk.java.net/jdk17u-dev/pull/91.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17u-dev pull/91/head:pull/91

PR: https://git.openjdk.java.net/jdk17u-dev/pull/91