RFR: 8341197: [BACKOUT] 8322770: Implement C2 VectorizedHashCode on AArch64

[Tobias Hartmann]

Let's backout [JDK-8322770](https://bugs.openjdk.org/browse/JDK-8322770) while we investigate [JDK-8341194](https://bugs.openjdk.org/browse/JDK-8341194). Applies cleanly.

Thanks,
Tobias

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Commit messages:
 - Revert "8322770: Implement C2 VectorizedHashCode on AArch64"

Changes: https://git.openjdk.org/jdk/pull/21260/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21260&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8341197
  Stats: 1355 lines in 11 files changed: 0 ins; 775 del; 580 mod
  Patch: https://git.openjdk.org/jdk/pull/21260.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21260/head:pull/21260

PR: https://git.openjdk.org/jdk/pull/21260