Fix file error tests on Windows

tests/standalone/src/io/FileErrorTest.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 212 matching lines @@
   file.createSync();
   var openedFile = file.openSync(FileMode.READ);
 
   // Writing to read only file should throw an exception.
   Expect.throws(() => openedFile.writeByteSync(0),
                 (e) => checkWriteReadOnlyFileException(e));
 
   openedFile.writeByte(0);
   openedFile.onError = (e) {
     checkWriteReadOnlyFileException(e);
-    p.toSendPort().send(null);
+    openedFile.close(() => p.toSendPort().send(null));
   };
 }
 
 testWriteListToReadOnlyFile() {
   Directory temp = tempDir();
   ReceivePort p = new ReceivePort();
   p.receive((x,y) {
     p.close();
     temp.deleteRecursivelySync();
   });
 
   var file = new File("${temp.path}/test_file");
   file.createSync();
   var openedFile = file.openSync(FileMode.READ);
 
   List data = [0, 1, 2, 3];
   // Writing to read only file should throw an exception.
   Expect.throws(() => openedFile.writeListSync(data, 0, data.length),
                 (e) => checkWriteReadOnlyFileException(e));
 
   openedFile.writeList(data, 0, data.length);
   openedFile.onError = (e) {
     checkWriteReadOnlyFileException(e);
-    p.toSendPort().send(null);
+    openedFile.close(() => p.toSendPort().send(null));
   };
 }
 
 testTruncateReadOnlyFile() {
   Directory temp = tempDir();
   ReceivePort p = new ReceivePort();
   p.receive((x,y) {
     p.close();
     temp.deleteRecursivelySync();
   });
 
   var file = new File("${temp.path}/test_file");
   file.createSync();
-  var openedFile = file.openSync(FileMode.READ);
+  var openedFile = file.openSync(FileMode.WRITE);
+  openedFile.writeByteSync(0);
+  openedFile.closeSync();
+  openedFile = file.openSync(FileMode.READ);
 
   // Truncating read only file should throw an exception.
   Expect.throws(() => openedFile.truncateSync(0),
                 (e) => checkWriteReadOnlyFileException(e));
 
   openedFile.truncate(0, () => Expect.fail("Unreachable code"));
   openedFile.onError = (e) {
     checkWriteReadOnlyFileException(e);
-    p.toSendPort().send(null);
+    openedFile.close(() => p.toSendPort().send(null));
   };
 }
 
 bool checkFileClosedException(e) {
   Expect.isTrue(e is FileIOException);
   Expect.isTrue(e.toString().indexOf("File closed") != -1);
   Expect.isTrue(e.osError == null);
   return true;
 }
 
@@ skipping 70 matching lines @@
   testFullPathOnNonExistentDirectory();
   testDirectoryInNonExistentDirectory();
   testReadAsBytesNonExistent();
   testReadAsTextNonExistent();
   testReadAsLinesNonExistent();
   testWriteByteToReadOnlyFile();
   testWriteListToReadOnlyFile();
   testTruncateReadOnlyFile();
   testOperateOnClosedFile();
 }