[jdk21u-dev] RFR: 8333652: RISC-V: compiler/vectorapi/VectorGatherMaskFoldingTest.java fails when using RVV

[Gui Cao]

Hi, The same issue also exists in the JDK21U: I can reproduce it locally and use this clean patch can fix that issue, So I would like to backport this to JDK21U. This is a risc-v specific change. Backport is clean, risk is low.

### Testing
- [x] test/jdk/jdk/incubator/vector on Banana Pi BPI-F3 board (with RVV1.0)

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Commit messages:
 - Backport ce5727df4436425b24b89f24c6e6b708575ec7c6

Changes: https://git.openjdk.org/jdk21u-dev/pull/708/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=708&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8333652
  Stats: 86 lines in 2 files changed: 70 ins; 2 del; 14 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/708.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/708/head:pull/708

PR: https://git.openjdk.org/jdk21u-dev/pull/708