RFR: 8358768: [vectorapi] Make VectorOperators.SUADD an Associative [v3]

[Ian Graves]

> Adding SUADD an associative operation in the Vector API. Saturated addition on fixed-width unsigned integers is provably associative.

Ian Graves has updated the pull request incrementally with one additional commit since the last revision:

  Cleaning up test cases

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26099/files
  - new: https://git.openjdk.org/jdk/pull/26099/files/6c8d8952..8cfc55ee

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26099&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26099&range=01-02

  Stats: 611 lines in 21 files changed: 568 ins; 0 del; 43 mod
  Patch: https://git.openjdk.org/jdk/pull/26099.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26099/head:pull/26099

PR: https://git.openjdk.org/jdk/pull/26099