Optimize functions containing try-catch.

tests/language/try_catch_test.dart

 // Copyright (c) 2011, 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.
 
 import "package:expect/expect.dart";
 
 class MyException { }
 
 class MyException1 extends MyException { }
 
@@ skipping 133 matching lines @@
     test4();
     test5();
     test6();
     test7();
     test8();
     test9();
   }
 }
 
 main() {
-  TryCatchTest.testMain();
+  for (var i = 0; i < 2000; i++) {
+    TryCatchTest.testMain();
+  }
 }