RFR: 8355562: RISC-V: Cleanup names of vector-scalar instructions in riscv_v.ad

[Anjian-Wen]

RISC-V: Cleanup names of vector-scalar instructions in riscv_v.ad

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Commit messages:
 - RISC-V: Cleanup names of vector-scalar instructions in riscv_v.ad

Changes: https://git.openjdk.org/jdk/pull/24865/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24865&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355562
  Stats: 146 lines in 1 file changed: 0 ins; 0 del; 146 mod
  Patch: https://git.openjdk.org/jdk/pull/24865.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24865/head:pull/24865

PR: https://git.openjdk.org/jdk/pull/24865