More tests updated to optimize code (Part 2).

tests/language/load_to_load_forwarding_vm_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.
 // Test correctness of side effects tracking used by load to load forwarding.
 
 // VMOptions=--optimization-counter-threshold=10
 
 import "package:expect/expect.dart";
 import "dart:typed_data";
 
@@ skipping 213 matching lines @@
   Expect.equals(1, testImmutableVMFields([], false));
   Expect.equals(2, testImmutableVMFields([1], false));
   Expect.equals(2, testImmutableVMFields([1, 2], false));
   Expect.equals(3, testImmutableVMFields([1, 2, 3], false));
 
   final u32List = new Uint32List(3);
   u32List[0] = 0;
   u32List[1] = 0x3FFFFFFF;
   u32List[2] = 0x7FFFFFFF;
 
-  for (var i = 0; i < 4000; i++) {
+  for (var i = 0; i < 20; i++) {
     testPhiConvertions(true, u32List);
     testPhiConvertions(false, u32List);
   }
 
   final escape = new List(1);
-  for (var i = 0; i < 10000; i++) {
+  for (var i = 0; i < 20; i++) {
     fakeAliasing(escape);
   }
 }