[turbofan] Implemented the ChangeFloat64ToInt64 TurboFan operator.

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 b687cad47a92886e994bf0a61909b199c3f5f300..7b71333b8370afd6d8b7b4ade35edc3d9ee977c2 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -202,6 +202,7 @@ class MachineOperatorBuilder final : public ZoneObject {
   const Operator* ChangeFloat32ToFloat64();
   const Operator* ChangeFloat64ToInt32();   // narrowing
   const Operator* ChangeFloat64ToUint32();  // narrowing
+  const Operator* ChangeFloat64ToInt64();   // narrowing
   const Operator* ChangeInt32ToFloat64();
   const Operator* ChangeInt32ToInt64();
   const Operator* ChangeUint32ToFloat64();