RFR: 8368205: [TESTBUG] VectorMaskCompareNotTest.java crashes when MaxVectorSize=8

[erifan]

The VectorShape size of `I_SPECIES_FOR_CAST` declared in test **VectorMaskCompareNotTest.java** is half that of `L_SPECIES_FOR_CAST`. And `L_SPECIES_FOR_CAST` is created with the maximum shape. Therefore, if `MaxVectorSize` is set to 8, the shape size of `I_SPECIES_FOR_CAST` is 4, which is an illegal value because the minimum vector size requirement is 8 bytes.

This pull request addresses the issue by ensuring that this test runs only when `MaxVectorSize` is set to 16 bytes or higher.

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Commit messages:
 - 8368205: [TESTBUG] VectorMaskCompareNotTest.java crashes when MaxVectorSize=8

Changes: https://git.openjdk.org/jdk/pull/27418/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27418&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368205
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27418.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27418/head:pull/27418

PR: https://git.openjdk.org/jdk/pull/27418