Another attempt to fix flaky test.

tests/standalone/src/FileTest.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 file I/O.
 
 #import("dart:io");
 #import("dart:isolate");
 
 class MyListOfOneElement implements List {
@@ skipping 104 matching lines @@
             Expect.isTrue(input.closed);
 
             // Write the contents of the file just read into another file.
             String outFilename = tempDirectory.path + "/out_read_write_stream";
             file = new File(outFilename);
             OutputStream output = file.openOutputStream();
             bool writeDone = output.writeFrom(buffer1, 0, 42);
             Expect.equals(false, writeDone);
             output.noPendingWriteHandler = () {
               output.close();
-
-              // Now read the contents of the file just written.
-              List<int> buffer2 = new List<int>(42);
-              file = new File(outFilename);
-              input = file.openInputStream();
-              input.dataHandler = () {
-                bytesRead = input.readInto(buffer2, 0, 42);
-                Expect.equals(42, bytesRead);
-                // Now compare the two buffers to check if they are identical.
-                for (int i = 0; i < buffer1.length; i++) {
-                  Expect.equals(buffer1[i],  buffer2[i]);
-                }
+              output.closeHandler = () {
+                // Now read the contents of the file just written.
+                List<int> buffer2 = new List<int>(42);
+                file = new File(outFilename);
+                input = file.openInputStream();
+                input.dataHandler = () {
+                  bytesRead = input.readInto(buffer2, 0, 42);
+                  Expect.equals(42, bytesRead);
+                  // Now compare the two buffers to check if they are identical.
+                  for (int i = 0; i < buffer1.length; i++) {
+                    Expect.equals(buffer1[i],  buffer2[i]);
+                  }
+                };
                 input.closeHandler = () {
                   // Delete the output file.
                   file.deleteSync();
                   Expect.isFalse(file.existsSync());
                   asyncTestDone("testReadWriteStream");
                 };
               };
             };
           };
         };
@@ skipping 1000 matching lines @@
       testWriteVariousLists();
       testDirectory();
       testDirectorySync();
     });
   }
 }
 
 main() {
   FileTest.testMain();
 }