RFR: 8346174: UMAX/UMIN are missing from XXXVector::reductionOperations

[Paul Sandoz]

Add functional support for unsigned min/max reductions on vectors.

We also need to ensure that the `reductionCoerced` intrinsic bails out when there is no reduction operation for the lanewise operation. When intrinsic support is added for integral vectors this will still be the case for floating point vectors.

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Commit messages:
 - Functional support for unsigned min/max reductions.

Changes: https://git.openjdk.org/jdk/pull/22741/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22741&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346174
  Stats: 3590 lines in 27 files changed: 3590 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22741.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22741/head:pull/22741

PR: https://git.openjdk.org/jdk/pull/22741