Add boolean flag to HChange and LNumberUntagD to not convert undefined to NaN.

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 507667ea86b522dfc9a7e30b88588ef5780dcf99..46af67cc81c9164f6f21219210893fe5169c7231 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -1646,11 +1646,17 @@ class LSmiTag: public LTemplateInstruction<1, 1, 0> {
 
 class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
  public:
-  explicit LNumberUntagD(LOperand* value) {
+  LNumberUntagD(LOperand* value, bool deoptimize_on_undefined)
+      : deoptimize_on_undefined_(deoptimize_on_undefined) {
     inputs_[0] = value;
   }
 
+  bool deoptimize_on_undefined() { return deoptimize_on_undefined_; }
+
   DECLARE_CONCRETE_INSTRUCTION(NumberUntagD, "double-untag")
+
+ private:
+  bool deoptimize_on_undefined_;
 };