[turbofan] Add the RoundInt32ToFloat32 operator to turbofan.

src/compiler/arm64/code-generator-arm64.cc

Index: src/compiler/arm64/code-generator-arm64.cc
diff --git a/src/compiler/arm64/code-generator-arm64.cc b/src/compiler/arm64/code-generator-arm64.cc
index d356195ecfbb76075e1cd821719fcbe9bc2121b9..916a4a6ec13a31f937dd126d1b951668abdbedb7 100644
--- a/src/compiler/arm64/code-generator-arm64.cc
+++ b/src/compiler/arm64/code-generator-arm64.cc
@@ -1093,6 +1093,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
         __ Cset(i.OutputRegister(1), ne);
       }
       break;
+    case kArm64Int32ToFloat32:
+      __ Scvtf(i.OutputFloat32Register(), i.InputRegister32(0));
+      break;
     case kArm64Int32ToFloat64:
       __ Scvtf(i.OutputDoubleRegister(), i.InputRegister32(0));
       break;