Remove more feature in product mode

runtime/vm/debugger_arm64.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
 #include "vm/debugger.h"
 #include "vm/instructions.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
+#ifndef PRODUCT
+
 RawCode* CodeBreakpoint::OrigStubAddress() const {
   return saved_value_;
 }
 
 
 void CodeBreakpoint::PatchCode() {
   ASSERT(!is_enabled_);
   Code& stub_target = Code::Handle();
   switch (breakpoint_kind_) {
     case RawPcDescriptors::kIcCall:
@@ skipping 24 matching lines @@
       CodePatcher::PatchPoolPointerCallAt(
           pc_, code, Code::Handle(saved_value_));
       break;
     }
     default:
       UNREACHABLE();
   }
   is_enabled_ = false;
 }
 
+#endif  // !PRODUCT
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64