RFR: 8369511: PPC64: compiler/vectorapi/VectorMaskCompareNotTest.java fails when running without VectorRegisters

[Martin Doerr]

The test `VectorMaskCompareNotTest` requires 16 Byte vectors (or larger). If the machine only uses 8 Byte vectors, we get an exception in the static initializer because the code tries to use a 4 Byte vector which is unsupported (stack trace: see JBS issue). This is an alternative to https://github.com/openjdk/jdk/pull/27749.

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Commit messages:
 - 8369511: PPC64: compiler/vectorapi/VectorMaskCompareNotTest.java fails when running without VectorRegisters

Changes: https://git.openjdk.org/jdk/pull/27805/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27805&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369511
  Stats: 22 lines in 2 files changed: 21 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27805.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27805/head:pull/27805

PR: https://git.openjdk.org/jdk/pull/27805