[riscv-port-jdk17u:riscv-port] RFR: 8300109: RISC-V: Improve code generation for MinI/MaxI nodes

[Dingli Zhang]

Please review this backport to riscv-port-jdk17u.
Backport of [JDK-8300109](https://bugs.openjdk.org/browse/JDK-8300109). Applies cleanly.

Testing:

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

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Commit messages:
 - 8300109: RISC-V: Improve code generation for MinI/MaxI node

Changes: https://git.openjdk.org/riscv-port-jdk17u/pull/25/files
 Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk17u&pr=25&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8300109
  Stats: 92 lines in 1 file changed: 90 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/riscv-port-jdk17u/pull/25.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk17u.git pull/25/head:pull/25

PR: https://git.openjdk.org/riscv-port-jdk17u/pull/25