Don't close stdio/stderr when shutting down.

runtime/bin/file.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.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "bin/file.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
@@ skipping 95 matching lines @@
   const char* filename =
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
   bool exists = File::Exists(filename);
   Dart_SetReturnValue(args, Dart_NewBoolean(exists));
 }
 
 
 void FUNCTION_NAME(File_Close)(Dart_NativeArguments args) {
   File* file = GetFile(args);
   ASSERT(file != NULL);
+  file->Close();
   file->DeleteWeakHandle(Dart_CurrentIsolate());
   file->Release();
 
   // NULL-out the now potentially dangling pointer.
   Dart_Handle dart_this = Dart_GetNativeArgument(args, 0);
   SetFile(dart_this, 0);
   Dart_SetReturnValue(args, Dart_NewInteger(0));
 }
 
 
@@ skipping 1103 matching lines @@
       return CObject::IllegalArgumentError();
     }
   }
   return CObject::IllegalArgumentError();
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // !defined(DART_IO_DISABLED)