[turbofan]: Convert StringFromCharCode to var-args style TF builtin

src/code-stub-assembler.h

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 1089 matching lines @@
                               compiler::Node* context);
 
   compiler::Node* Typeof(compiler::Node* value, compiler::Node* context);
 
   compiler::Node* InstanceOf(compiler::Node* object, compiler::Node* callable,
                              compiler::Node* context);
 
   // TypedArray/ArrayBuffer helpers
   compiler::Node* IsDetachedBuffer(compiler::Node* buffer);
 
+  compiler::Node* ElementOffsetFromIndex(compiler::Node* index,
+                                         ElementsKind kind, ParameterMode mode,
+                                         int base_size = 0);
+
  private:
   friend class CodeStubArguments;
 
   enum ElementSupport { kOnlyProperties, kSupportElements };
 
   void DescriptorLookupLinear(compiler::Node* unique_name,
                               compiler::Node* descriptors, compiler::Node* nof,
                               Label* if_found, Variable* var_name_index,
                               Label* if_not_found);
   compiler::Node* CallGetterIfAccessor(compiler::Node* value,
@@ skipping 40 matching lines @@
   void EmitElementLoad(compiler::Node* object, compiler::Node* elements,
                        compiler::Node* elements_kind, compiler::Node* key,
                        compiler::Node* is_jsarray_condition, Label* if_hole,
                        Label* rebox_double, Variable* var_double_value,
                        Label* unimplemented_elements_kind, Label* out_of_bounds,
                        Label* miss);
   void BranchIfPrototypesHaveNoElements(compiler::Node* receiver_map,
                                         Label* definitely_no_elements,
                                         Label* possibly_elements);
 
-  compiler::Node* ElementOffsetFromIndex(compiler::Node* index,
-                                         ElementsKind kind, ParameterMode mode,
-                                         int base_size = 0);
-
   compiler::Node* AllocateRawAligned(compiler::Node* size_in_bytes,
                                      AllocationFlags flags,
                                      compiler::Node* top_address,
                                      compiler::Node* limit_address);
   compiler::Node* AllocateRawUnaligned(compiler::Node* size_in_bytes,
                                        AllocationFlags flags,
                                        compiler::Node* top_adddress,
                                        compiler::Node* limit_address);
   // Allocate and return a JSArray of given total size in bytes with header
   // fields initialized.
@@ skipping 81 matching lines @@
   }
 #else
 #define CSA_SLOW_ASSERT(x)
 #endif
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_