Add missing closed check to random access file.

tests/standalone/io/file_error_test.dart

 // 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.
 //
 // Dart test program for testing error handling in file I/O.
 
 #import("dart:io");
 #import("dart:isolate");
 
 Directory tempDir() {
@@ skipping 472 matching lines @@
       closeFuture.handleException((e) {
         Expect.isTrue(e is FileIOException);
         port.send(null);
         return true;
       });
       closeFuture.then((ignore) => null);
     });
   });
 }
 
+testRepeatedlyCloseFileSync() {
+  createTestFile((file, port) {
+    var openedFile = file.openSync();
+    openedFile.closeSync();
+    Expect.throws(openedFile.closeSync,
+                  (e) => e is FileIOException);
+    port.send(null);
+  });
+}
+
 main() {
   testOpenNonExistent();
   testDeleteNonExistent();
   testLengthNonExistent();
   testCreateInNonExistentDirectory();
   testFullPathOnNonExistentDirectory();
   testDirectoryInNonExistentDirectory();
   testReadAsBytesNonExistent();
   testReadAsTextNonExistent();
   testReadAsLinesNonExistent();
   testWriteByteToReadOnlyFile();
   testWriteListToReadOnlyFile();
   testTruncateReadOnlyFile();
   testOperateOnClosedFile();
   testRepeatedlyCloseFile();
+  testRepeatedlyCloseFileSync();
 }