RFR: 8312164: Refactor Arrays.hashCode for long, boolean, and Object arrays

[Pavel Rappo]

Please review this PR to refactor Arrays.hashCode for long[], boolean[], and Object[]. I've been told elsewhere that it shouldn't have significant performance implications.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/14900/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14900&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312164
  Stats: 4 lines in 1 file changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/14900.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14900/head:pull/14900

PR: https://git.openjdk.org/jdk/pull/14900