[vm] Enable mirrors in product mode. Allows building a product mode SDK.

runtime/vm/bootstrap_natives.h

 // Copyright (c) 2012, 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.
 
 #ifndef RUNTIME_VM_BOOTSTRAP_NATIVES_H_
 #define RUNTIME_VM_BOOTSTRAP_NATIVES_H_
 
 #include "vm/native_entry.h"
 
 // bootstrap dart natives used in the core dart library.
@@ skipping 407 matching lines @@
   static Dart_NativeFunction Lookup(Dart_Handle name,
                                     int argument_count,
                                     bool* auto_setup_scope);
 
   static const uint8_t* Symbol(Dart_NativeFunction* nf);
 
 #define DECLARE_BOOTSTRAP_NATIVE(name, ignored)                                \
   static void DN_##name(Dart_NativeArguments args);
 
   BOOTSTRAP_NATIVE_LIST(DECLARE_BOOTSTRAP_NATIVE)
-#if !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
+#if !defined(DART_PRECOMPILED_RUNTIME)
   MIRRORS_BOOTSTRAP_NATIVE_LIST(DECLARE_BOOTSTRAP_NATIVE)
 #endif
 
 #undef DECLARE_BOOTSTRAP_NATIVE
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_BOOTSTRAP_NATIVES_H_