[turbofan] Add AllocateHeapNumberStub to avoid runtime call.

src/x64/interface-descriptors-x64.cc

Index: src/x64/interface-descriptors-x64.cc
diff --git a/src/x64/interface-descriptors-x64.cc b/src/x64/interface-descriptors-x64.cc
index bc058fff358c7f27300cd8353969e85fba0da479..f19979d4674773b9664bec255b226fc7fdb98a81 100644
--- a/src/x64/interface-descriptors-x64.cc
+++ b/src/x64/interface-descriptors-x64.cc
@@ -155,6 +155,15 @@ void TransitionElementsKindDescriptor::Initialize(
 }
 
 
+void AllocateHeapNumberDescriptor::Initialize(
+    CallInterfaceDescriptorData* data) {
+  // register state
+  // rsi -- context
+  Register registers[] = {rsi};
+  data->Initialize(arraysize(registers), registers, nullptr);
+}
+
+
 void ArrayConstructorConstantArgCountDescriptor::Initialize(
     CallInterfaceDescriptorData* data) {
   // register state