RFR: 8318220: RISC-V: C2 ReverseI

[Hamlin Li]

Hi,
Can you help to review this patch to add ReverseI and ReverseIL intrinsic on riscv?

Thanks!

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Commit messages:
 - clean test
 - clean test
 - clean test
 - clean
 - add tests
 - clean
 - merge master
 - rename rev_b to brev8
 - fix UseZbkb flag
 - merge master
 - ... and 1 more: https://git.openjdk.org/jdk/compare/18931d05...9bce9054

Changes: https://git.openjdk.org/jdk/pull/23963/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23963&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318220
  Stats: 292 lines in 10 files changed: 292 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23963.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23963/head:pull/23963

PR: https://git.openjdk.org/jdk/pull/23963