Update almost all tests (except co19) to use the new try-catch syntax.

tests/language/closure3_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 that a NullPointerException is thrown even when an expression
 // seems to be free of side-effects.
 
 test(x, y) {
   (() { x - y; })();
 }
 
 main() {
   try {
     test(null, 2);
     Expect.fail('Expected NullPointerException');
-  } catch (NullPointerException ex) {
+  } on NullPointerException catch (ex) {
     return;
   }
   Expect.fail('Expected NullPointerException');
 }