[turbofan] Add AllocateHeapNumberStub to avoid runtime call.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index 9832650f42d40d96c399725cf5df15657caecc21..552b7eb883d4dd01c3cac6392e870d0f79e51a99 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -697,6 +697,13 @@ void TransitionElementsKindStub::InitializeDescriptor(
 }
 
 
+void AllocateHeapNumberStub::InitializeDescriptor(
+    CodeStubDescriptor* descriptor) {
+  descriptor->Initialize(
+      Runtime::FunctionForId(Runtime::kAllocateHeapNumber)->entry);
+}
+
+
 void CompareNilICStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
   descriptor->Initialize(FUNCTION_ADDR(CompareNilIC_Miss));
   descriptor->SetMissHandler(