Simplify Hydrogen code stubs with variable argument count

src/x64/deoptimizer-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 88 matching lines @@
   for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
     input_->SetFrameSlot(i, Memory::uint64_at(tos + i));
   }
 }
 
 
 void Deoptimizer::SetPlatformCompiledStubRegisters(
     FrameDescription* output_frame, CodeStubInterfaceDescriptor* descriptor) {
   intptr_t handler =
       reinterpret_cast<intptr_t>(descriptor->deoptimization_handler_);
-  int params = descriptor->environment_length();
+  int params = descriptor->GetHandlerParameterCount();
   output_frame->SetRegister(rax.code(), params);
   output_frame->SetRegister(rbx.code(), handler);
 }
 
 
 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
   for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); ++i) {
     double double_value = input_->GetDoubleRegister(i);
     output_frame->SetDoubleRegister(i, double_value);
   }
@@ skipping 209 matching lines @@
   SetFrameSlot(offset, value);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64