[turbofan] Add initial support for growing stores.

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 1460b3c86562d86c87c25362f34585d60057fce4..dce4d97b908771490e412cc308d46631ef8e78ee 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -55,7 +55,7 @@ class PlatformInterfaceDescriptor;
   V(ConstructStub)                     \
   V(ConstructTrampoline)               \
   V(RegExpConstructResult)             \
-  V(CopyFixedArray)                    \
+  V(CopyFastSmiOrObjectElements)       \
   V(TransitionElementsKind)            \
   V(AllocateHeapNumber)                \
   V(AllocateFloat32x4)                 \
@@ -649,11 +649,11 @@ class StoreGlobalViaContextDescriptor : public CallInterfaceDescriptor {
   static const Register ValueRegister();
 };
 
-class CopyFixedArrayDescriptor : public CallInterfaceDescriptor {
+class CopyFastSmiOrObjectElementsDescriptor : public CallInterfaceDescriptor {
  public:
-  DEFINE_PARAMETERS(kSource)
-  DECLARE_DEFAULT_DESCRIPTOR(CopyFixedArrayDescriptor, CallInterfaceDescriptor,
-                             kParameterCount)
+  DEFINE_PARAMETERS(kObject)
+  DECLARE_DEFAULT_DESCRIPTOR(CopyFastSmiOrObjectElementsDescriptor,
+                             CallInterfaceDescriptor, kParameterCount)
 };
 
 class TransitionElementsKindDescriptor : public CallInterfaceDescriptor {
@@ -876,6 +876,7 @@ class VarArgFunctionDescriptor : public CallInterfaceDescriptor {
                                                CallInterfaceDescriptor)
 };
 
+// TODO(turbofan): We should probably rename this to GrowFastElementsDescriptor.
 class GrowArrayElementsDescriptor : public CallInterfaceDescriptor {
  public:
   DEFINE_PARAMETERS(kObject, kKey)