Intrinsify writing to Uint8 and Int8 arrays on IA32.

tests/standalone/byte_array_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 native byte arrays.
 
 // Library tag to be able to run in html test framework.
 #library("ByteArrayTest.dart");
 
 #import('dart:scalarlist');
 
 void testCreateByteArray() {
   Uint8List byteArray;
 
   byteArray = new Uint8List(0);
   Expect.equals(0, byteArray.length);
 
   byteArray = new Uint8List(10);
   Expect.equals(10, byteArray.length);
   for (int i = 0; i < 10; i++) {
     Expect.equals(0, byteArray[i]);
   }
+  byteArray[1] = 255;
+  Expect.equals(255, byteArray[1]);
+  byteArray[1] = 0;
+  Expect.equals(0, byteArray[1]);
+  // This should eventually throw.
+  byteArray[1] = 256;
 }
 
 void testSetRange() {
   Uint8List byteArray = new Uint8List(3);
 
   List<int> list = [10, 11, 12];
   byteArray.setRange(0, 3, list);
   for (int i = 0; i < 3; i++) {
     Expect.equals(10 + i, byteArray[i]);
   }
@@ skipping 46 matching lines @@
 }
 
 main() {
   for (int i = 0; i < 2000; i++) {
     testCreateByteArray();
     testSetRange();
     testIndexOutOfRange();
     testIndexOf();
   }
 }