RFR: 8320999: RISC-V: C2 RotateLeftV

[Hamlin Li]

Hi,
Can you help to review this patch?
More detailed description is inline in the code.
Thanks

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Commit messages:
 - add comments
 - fix mask
 - fix imm & long
 - fixes
 - Merge branch 'master' into rotate-left-right-v
 - fixes
 - remove redundant code: UseZvbb
 - merge master
 - RotateLeftV/RotateRightV: Initial Commit

Changes: https://git.openjdk.org/jdk/pull/19325/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19325&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320999
  Stats: 293 lines in 4 files changed: 285 ins; 3 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/19325.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19325/head:pull/19325

PR: https://git.openjdk.org/jdk/pull/19325