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

tests/language/try_catch2_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 program for testing try/catch statement without any exceptions
 // being thrown. (Nested try/catch blocks).
 
 interface TestException {
   String getMessage();
 }
 
 class MyException implements TestException {
   const MyException([String message = ""]) : message_ = message;
   String getMessage() { return message_; }
   final String message_;
 }
 
 class StackTrace {
   StackTrace() { }
 }
 
 class Helper {
   static int f1(int i) {
     try {
       int j;
       j = f2();
       i = i + 1;
       try {
         j = f2() + f3() + j;
         i = i + 1;
-      } catch (TestException e, StackTrace trace) {
+      } on TestException catch (e, trace) {
         j = 50;
       }
       j = f3() + j;
-    } catch (MyException exception) {
+    } on MyException catch (exception) {
       i = 100;
-    } catch (TestException e, StackTrace trace) {
+    } on TestException catch (e, trace) {
       i = 200;
     }
     return i;
   }
 
   static int f2() {
     return 2;
   }
 
   static int f3() {
     int i = 0;
     while (i < 10) {
       i++;
     }
     return i;
   }
 }
 
 class TryCatch2Test {
   static testMain() {
     Expect.equals(3, Helper.f1(1));
   }
 }
 
 main() {
   TryCatch2Test.testMain();
 }