Change a few more uses of the old try-catch syntax.

tests/language/try_catch3_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.
 
 interface TestException {
   String getMessage();
 }
 
@@ skipping 19 matching lines @@
 
 class Helper {
   static int test1(int i) {
     try {
       int j;
       j = f2();
       j = f3();
       try {
         int k = f2();
         f3();
-      } catch (MyException ex) {
+      } on MyException catch (ex) {
         int i = 10;
         print(i);
-      } catch (TestException ex) {
+      } on TestException catch (ex) {
         int k = 10;
         print(k);
       }
       try {
         j = j + 24;
-      } catch (var e) {
+      } catch (e) {
         i = 300;
         print(e.getMessage());
       }
       try {
         j += 20;
-      } catch (final e) {
+      } catch (e) {
         i = 400;
         print(e.getMessage());
       }
       try {
         j += 40;
-      } catch (var e) {
+      } catch (e) {
         i = 600;
         print(e.getMessage());
       }
       try {
         j += 60;
-      } catch (var e, var trace) {
+      } catch (e, trace) {
         i = 700;
         trace.printStackTrace(e);
         print(e.getMessage());
       }
       try {
         j += 80;
-      } catch (final MyException e) {
+      } on MyException catch (e) {
         i = 500;
         print(e.getMessage());
       }
-    } catch (MyParameterizedException<String, TestException> e, var trace) {
+    } on MyParameterizedException<String, TestException> catch (e, trace) {
       i = 800;
       trace.printStackTrace(e);
       throw;
-    } catch (MyException exception) {
+    } on MyException catch (exception) {
       i = 100;
       print(exception.getMessage());
-    } catch (TestException e, StackTrace trace) {
+    } on TestException catch (e, trace) {
       i = 200;
       trace.printStackTrace(e);
     } finally {
       i = 900;
     }
     return i;
   }
 
   static int f2() {
     return 2;
@@ skipping 10 matching lines @@
 
 class TryCatchTest {
   static testMain() {
     Expect.equals(900, Helper.test1(1));
   }
 }
 
 main() {
   TryCatchTest.testMain();
 }