[turbofan] Add the TruncateFloat32ToInt32 operator to turbofan.

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index 00fefe3539bc00dce5d37df2ab64621df61fb9c5..0495524a40150367ba573b59b3002d13c4a54a04 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -213,6 +213,7 @@ class MachineOperatorBuilder final : public ZoneObject {
   const Operator* ChangeFloat32ToFloat64();
   const Operator* ChangeFloat64ToInt32();   // narrowing
   const Operator* ChangeFloat64ToUint32();  // narrowing
+  const Operator* TruncateFloat32ToInt32();
   const Operator* TryTruncateFloat32ToInt64();
   const Operator* TryTruncateFloat64ToInt64();
   const Operator* TryTruncateFloat32ToUint64();