[riscv-port-jdk17u:riscv-port] RFR: 8301628: RISC-V: c2 fix pipeline class for several instructions

[Dingli Zhang]

Hi, please review this backport to riscv-port-jdk17u.
Backport of [JDK-8301628](https://bugs.openjdk.org/browse/JDK-8301628).
The original patch cannot be directly applied because jdk17u has no [JDK-8293695](https://bugs.openjdk.org/browse/JDK-8293695).

Testing:
- Tier1-3 passed without new failure on unmacthed (release).

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Commit messages:
 - 8301628: RISC-V: c2 fix pipeline class for several instructions

Changes: https://git.openjdk.org/riscv-port-jdk17u/pull/59/files
 Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk17u&pr=59&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301628
  Stats: 12 lines in 1 file changed: 0 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/riscv-port-jdk17u/pull/59.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk17u.git pull/59/head:pull/59

PR: https://git.openjdk.org/riscv-port-jdk17u/pull/59