Hydrogenize (and share) part of StoreTransition handler as a StoreTransitionStub.

src/interface-descriptors.cc

Index: src/interface-descriptors.cc
diff --git a/src/interface-descriptors.cc b/src/interface-descriptors.cc
index e9f76bdf2dbe29b8815abb01b8470aa81757690a..d41d53b14fa40d0d3d37ec5a1bca53fb6e726884 100644
--- a/src/interface-descriptors.cc
+++ b/src/interface-descriptors.cc
@@ -74,7 +74,7 @@ void StoreDescriptor::Initialize(CallInterfaceDescriptorData* data) {
 }
 
 
-void ExtendStorageDescriptor::Initialize(CallInterfaceDescriptorData* data) {
+void StoreTransitionDescriptor::Initialize(CallInterfaceDescriptorData* data) {
   Register registers[] = {ContextRegister(), ReceiverRegister(), NameRegister(),
                           ValueRegister(), MapRegister()};
   data->Initialize(arraysize(registers), registers, NULL);