[riscv64] Fix wasm-spec-tests/tests/func

Change-Id: I2e217b5b403db9fb8504a9c81040d8fe893b37d3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3740486Reviewed-by: ji qiu <qiuji@iscas.ac.cn>
Commit-Queue: Yahan Lu <yahan@iscas.ac.cn>
Commit-Queue: ji qiu <qiuji@iscas.ac.cn>
Cr-Commit-Position: refs/heads/main@{#81485}

src/wasm/baseline/riscv64/liftoff-assembler-riscv64.h

@@ -1052,17 +1052,19 @@ void LiftoffAssembler::Spill(int offset, WasmValue value) {
   MemOperand dst = liftoff::GetStackSlot(offset);
   switch (value.type().kind()) {
     case kI32: {
-      LiftoffRegister tmp = GetUnusedRegister(kGpReg, {});
-      TurboAssembler::li(tmp.gp(), Operand(value.to_i32()));
-      Sw(tmp.gp(), dst);
+      UseScratchRegisterScope temps(this);
+      Register tmp = temps.Acquire();
+      TurboAssembler::li(tmp, Operand(value.to_i32()));
+      Sw(tmp, dst);
       break;
     }
     case kI64:
     case kRef:
     case kOptRef: {
-      LiftoffRegister tmp = GetUnusedRegister(kGpReg, {});
-      TurboAssembler::li(tmp.gp(), value.to_i64());
-      Sd(tmp.gp(), dst);
+      UseScratchRegisterScope temps(this);
+      Register tmp = temps.Acquire();
+      TurboAssembler::li(tmp, value.to_i64());
+      Sd(tmp, dst);
       break;
     }
     default: