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

tests/language/savannah_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.
 // Dart test using an identity hash.
 
 interface BigGame extends Hashable {
   final String name;
 }
 
 class Giraffe implements BigGame {
@@ skipping 38 matching lines @@
     print("giraffe2: ${savannah[giraffe2]}");
     Expect.equals("Tony", savannah[giraffe1]);
     Expect.equals("Rose", savannah[giraffe2]);
 
     bool caught = false;
     Zebra zebra1 = new Zebra("Paul");
     Zebra zebra2 = new Zebra("Joe");
     try {
       savannah[zebra1] = zebra1.name;
       savannah[zebra2] = zebra2.name;
-    } catch (NoSuchMethodException e) {
+    } on NoSuchMethodException catch (e) {
       print("Caught: $e");
       caught = true;
     }
     Expect.equals(true, caught);
 
     count = savannah.length;
     print("getCount is $count");
     Expect.equals(2, count);
 
     caught = false;
     try {
       print("zebra1: ${savannah[zebra1]}");
       print("zebra2: ${savannah[zebra2]}");
-    } catch (NoSuchMethodException e) {
+    } on NoSuchMethodException catch (e) {
       print("Caught: $e");
       caught = true;
     }
     Expect.equals(true, caught);
   }
 
 }
 
 main() {
   SavannahTest.testMain();
 }