[stubs] Port StoreFastElementsStub to TurboFan.

src/compiler/code-assembler.cc

Index: src/compiler/code-assembler.cc
diff --git a/src/compiler/code-assembler.cc b/src/compiler/code-assembler.cc
index 7f8e2ffad0e5f4f1a97ed96db9e0adf542aab44f..a7eac95755b973efb7db14908f733e8aa0a5ecf6 100644
--- a/src/compiler/code-assembler.cc
+++ b/src/compiler/code-assembler.cc
@@ -306,6 +306,10 @@ Node* CodeAssembler::StoreRoot(Heap::RootListIndex root_index, Node* value) {
                              IntPtrConstant(root_index * kPointerSize), value);
 }
 
+Node* CodeAssembler::Retain(Node* value) {
+  return raw_assembler_->Retain(value);
+}
+
 Node* CodeAssembler::Projection(int index, Node* value) {
   return raw_assembler_->Projection(index, value);
 }