[turbofan] Avoid going through ArgumentsAdaptorTrampoline for CSA/C++ builtins

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index 74c23c67f1033633a6698d997b99ebd47597c252..eeec089a2f368878e53aa8c36fc898453a092b72 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -1454,11 +1454,12 @@ class CodeStubArguments {
  public:
   typedef compiler::Node Node;
 
-  // |argc| is an uint32 value which specifies the number of arguments passed
+  // |argc| is an intptr value which specifies the number of arguments passed
   // to the builtin excluding the receiver.
   CodeStubArguments(CodeStubAssembler* assembler, Node* argc)
       : CodeStubArguments(assembler, argc, nullptr,
                           CodeStubAssembler::INTPTR_PARAMETERS) {}
+  // |argc| is either a smi or intptr depending on |param_mode|
   CodeStubArguments(CodeStubAssembler* assembler, Node* argc, Node* fp,
                     CodeStubAssembler::ParameterMode param_mode);
 
@@ -1473,6 +1474,8 @@ class CodeStubArguments {
 
   Node* AtIndex(int index) const;
 
+  Node* GetOptionalArgumentValue(int index, Node* default_value);
+
   Node* GetLength() const { return argc_; }
 
   typedef std::function<void(Node* arg)> ForEachBodyFunction;