RFR: 8332826: Make hashCode methods in ArraysSupport friendlier [v3]

[Pavel Rappo]

> Please review this PR, which supersedes a now withdrawn https://github.com/openjdk/jdk/pull/14831.
> 
> This PR replaces `ArraysSupport.vectorizedHashCode` with a set of more user-friendly methods. Here's a summary:
> 
> - Made the operand constants (i.e. `T_BOOLEAN` and friends) and the `vectorizedHashCode` method private
> 
> - Made the `vectorizedHashCode` method private, but didn't rename it. Renaming would dramatically increase this PR review cost, because that method's name is used by a lot of VM code. On a bright side, since the method is now private, it's no longer callable by clients of `ArraysSupport`, thus a problem of an inaccurate name is less severe.
> 
> - Made the `ArraysSupport.utf16HashCode` method private
> 
> - Moved tiny cases (i.e. 0, 1, 2) to `ArraysSupport`

Pavel Rappo has updated the pull request incrementally with three additional commits since the last revision:

 - Update copyright years
   
   Note: any commit hashes below might be outdated due to subsequent
   history rewriting (e.g. git rebase).
   
    + update src/java.base/share/classes/java/lang/CharacterName.java due to 4ed451d691c
    + update src/java.base/share/classes/java/lang/StringLatin1.java due to 4ed451d691c
    + update src/java.base/share/classes/java/nio/Heap-X-Buffer.java.template due to 4ed451d691c
    + update src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPoolEntry.java due to 4ed451d691c
    + update src/java.base/share/classes/sun/security/util/DerValue.java due to 4ed451d691c
    + update src/java.base/unix/classes/sun/nio/fs/UnixPath.java due to 4ed451d691c
    + update test/hotspot/jtreg/compiler/intrinsics/TestArraysHashCode.java due to 4ed451d691c
 - Drop redundant (int) cast
 - Use Byte.toUnsignedInt not & 0xff

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19414/files
  - new: https://git.openjdk.org/jdk/pull/19414/files/adc7557d..53d4ed09

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19414&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19414&range=01-02

  Stats: 12 lines in 8 files changed: 0 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/19414.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19414/head:pull/19414

PR: https://git.openjdk.org/jdk/pull/19414