[llvm] [Exegesis][RISCV] Add RISCV support for llvm-exegesis (PR #89047)

[Michael Maitland via llvm-commits]

================
@@ -52,13 +52,16 @@ computeAliasingInstructions(const LLVMState &State, const Instruction *Instr,
       continue;
     if (OtherOpcode == Instr->Description.getOpcode())
       continue;
+    if (!State.getExegesisTarget().checkOpcodeSupported(
----------------
michaelmaitland wrote:

Are these changes RISC-V specific? Could they be split into a separate patch?

https://github.com/llvm/llvm-project/pull/89047