RFR: 8368247: RISC-V: enable vectorapi test for expand operation

[Dingli Zhang]

Hi,
Can you help to review this patch? Thanks!

[JDK-8363989](https://bugs.openjdk.org/browse/JDK-8363989) adds a vectorapi test for VectorAPI expand operation, which we can also enable on RISC-V.

### Test (fastdebug)
- [x] Run compiler/vectorapi/VectorExpandTest.java on k1 and sg2042

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Commit messages:
 - 8368247: RISC-V: enable vectorapi test for expand operation

Changes: https://git.openjdk.org/jdk/pull/27420/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27420&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368247
  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/27420.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27420/head:pull/27420

PR: https://git.openjdk.org/jdk/pull/27420