More tests updated to optimize code (Part 2).

tests/language/try_catch4_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.
 // Check that our SSA graph does have the try body a predecessor of a
 // try/finally.
+// VMOptions=--optimization-counter-threshold=10
 
 import "package:expect/expect.dart";
 
 var a;
 
 foo1() {
   var b = false;
   var entered = false;
   while (true) {
     if (entered) return b;
@@ skipping 174 matching lines @@
   Expect.isTrue(foo6());
   a = 0;
   Expect.isTrue(foo7());
   a = 0;
   Expect.isTrue(foo8());
   a = 0;
   Expect.isTrue(foo9());
 }
 
 main() {
-  for (var i = 0; i < 2000; i++) {
+  for (var i = 0; i < 20; i++) {
     main_test();
   }
 }