Don't pass --print_snapshot_sizes in product mode

runtime/bin/gen_snapshot.cc

 // Copyright (c) 2013, 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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 1188 matching lines @@
   TimerUtils::InitOnce();
   EventHandler::Start();
 
 #if !defined(PRODUCT)
   // Constant true in PRODUCT mode.
   vm_options.AddArgument("--load_deferred_eagerly");
 #endif
 
   if (IsSnapshottingForPrecompilation()) {
     vm_options.AddArgument("--precompilation");
+#if !defined(PRODUCT)
     vm_options.AddArgument("--print_snapshot_sizes");
+#endif
 #if TARGET_ARCH_ARM
     // This is for the iPod Touch 5th Generation (and maybe other older devices)
     vm_options.AddArgument("--no-use_integer_division");
 #endif
   }
 
   Dart_SetVMFlags(vm_options.count(), vm_options.arguments());
 
   // Initialize the Dart VM.
   // Note: We don't expect isolates to be created from dart code during
@@ skipping 145 matching lines @@
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }