RFR: 8321014: RISC-V: C2 VectorLoadShuffle

[Hamlin Li]

Hi,
Can you help to review the patch for instrinsic VectorLoadShuffle?

BTW, without this intrinsic, some other vector api operation does not work as well (e.g. rearrange) on riscv.

Thanks

## Test
test/jdk/jdk/incubator/vector/
test/hotspot/jtreg/compiler/vectorapi

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/18835/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18835&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8321014
  Stats: 42 lines in 1 file changed: 42 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18835.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18835/head:pull/18835

PR: https://git.openjdk.org/jdk/pull/18835