Support for type dynamic in VM

tests/language/closure_type_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 for a closure result type test that cannot be eliminated at compile
 // time.
 
 #library('closure_type_test');
 #import('dart:math', prefix: 'math');
 
 class Math {
   static int sqrt(x) => math.sqrt(x);
 }
 
 isCheckedMode() {
   try {
     var i = 1;
     String s = i;
     return false;
   } catch (e) {
     return true;
   }
 }
 
 
 void test(int func(int value), int value) {
   bool got_type_error = false;
   try {
     // Because of function subtyping rules, the static return type of a closure
     // call cannot be relied upon for static type analysis. For example, a
-    // function returning Dynamic (function 'root') can be assigned to a closure
+    // function returning dynamic (function 'root') can be assigned to a closure
     // variable declared to return int (closure 'func') and may actually return
     // a double at run-time.
     // Therefore, eliminating the run-time type check would be wrong.
     int x = func(value);
     Expect.equals(value, x * x);
   } on TypeError catch (error) {
     got_type_error = true;
   }
   // Type error expected in checked mode only.
   Expect.isTrue(got_type_error == isCheckedMode());
 }
 
 root(x) => Math.sqrt(x);
 
 main() => test(root, 4);