[turbofan] Initial version of allocation folding and write barrier elimination.

src/interface-descriptors.cc

Index: src/interface-descriptors.cc
diff --git a/src/interface-descriptors.cc b/src/interface-descriptors.cc
index 586701fdfa37a2a93699a17450f79a8aeea0337d..c0a342c87e60c63152b01a5823bd5696d3034278 100644
--- a/src/interface-descriptors.cc
+++ b/src/interface-descriptors.cc
@@ -75,12 +75,6 @@ const char* CallInterfaceDescriptor::DebugName(Isolate* isolate) const {
 }
 
 
-void AllocateMutableHeapNumberDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
-  data->InitializePlatformSpecific(0, nullptr, nullptr);
-}
-
-
 void VoidDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   data->InitializePlatformSpecific(0, nullptr);