fix performance regression on intel call api stubs

src/ic/x64/handler-compiler-x64.cc

 // Copyright 2014 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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ic/call-optimization.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 129 matching lines @@
   // Write the arguments to stack frame.
   if (is_store) {
     DCHECK(!receiver.is(store_parameter));
     DCHECK(!scratch_in.is(store_parameter));
     __ Push(store_parameter);
   }
   __ PushReturnAddressFrom(scratch_in);
   // Stack now matches JSFunction abi.
 
   // Abi for CallApiFunctionStub.
-  Register callee = rax;
+  Register callee = rdi;
   Register call_data = rbx;
   Register holder = rcx;
   Register api_function_address = rdx;
-  Register scratch = rdi;  // scratch_in is no longer valid.
+  Register scratch = rax;  // scratch_in is no longer valid.
 
   // Put holder in place.
   CallOptimization::HolderLookup holder_lookup;
   Handle<JSObject> api_holder =
       optimization.LookupHolderOfExpectedType(receiver_map, &holder_lookup);
   switch (holder_lookup) {
     case CallOptimization::kHolderIsReceiver:
       __ Move(holder, receiver);
       break;
     case CallOptimization::kHolderFound:
@@ skipping 582 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64