[stubs] Drop CallApiCallbackStub::call_data_undefined optimization.

src/x64/code-stubs-x64.cc

 // Copyright 2013 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 2725 matching lines @@
   __ PushRoot(Heap::kUndefinedValueRootIndex);
 
   // context save
   __ Push(context);
 
   // callee
   __ Push(callee);
 
   // call data
   __ Push(call_data);
+
+  // return value
+  __ PushRoot(Heap::kUndefinedValueRootIndex);
+  // return value default
+  __ PushRoot(Heap::kUndefinedValueRootIndex);
+  // isolate
   Register scratch = call_data;
-  if (!this->call_data_undefined()) {
-    __ LoadRoot(scratch, Heap::kUndefinedValueRootIndex);
-  }
-  // return value
-  __ Push(scratch);
-  // return value default
-  __ Push(scratch);
-  // isolate
   __ Move(scratch, ExternalReference::isolate_address(masm->isolate()));
   __ Push(scratch);
   // holder
   __ Push(holder);
 
   __ movp(scratch, rsp);
   // Push return address back on stack.
   __ PushReturnAddressFrom(return_address);
 
   if (!this->is_lazy()) {
@@ skipping 131 matching lines @@
                            kStackUnwindSpace, nullptr, return_value_operand,
                            NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64