[es6] re-implement rest parameters via desugaring

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 5237e7c8cca01b2adfe4b82b15d79db199357d29..04808a8615e88b69de3a9d32549f20e98322ee9a 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -273,28 +273,6 @@ void FullCodeGenerator::Generate() {
     SetVar(new_target_var, rax, rbx, rdx);
   }
 
-  // Possibly allocate RestParameters
-  int rest_index;
-  Variable* rest_param = scope()->rest_parameter(&rest_index);
-  if (rest_param) {
-    Comment cmnt(masm_, "[ Allocate rest parameter array");
-
-    int num_parameters = info->scope()->num_parameters();
-    int offset = num_parameters * kPointerSize;
-
-    __ leap(rdx,
-            Operand(rbp, StandardFrameConstants::kCallerSPOffset + offset));
-    __ Push(rdx);
-    __ Push(Smi::FromInt(num_parameters));
-    __ Push(Smi::FromInt(rest_index));
-    __ Push(Smi::FromInt(language_mode()));
-
-    RestParamAccessStub stub(isolate());
-    __ CallStub(&stub);
-
-    SetVar(rest_param, rax, rbx, rdx);
-  }
-
   // Possibly allocate an arguments object.
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {