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

tests/language/throw4_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 throw statement
 
 class MyException1 {
   const MyException1([String message = "1"]) : message_ = message;
   final String message_;
 }
 
 class MyException2 {
   const MyException2([String message = "2"]) : message_ = message;
   final String message_;
 }
 
 class MyException3 {
   const MyException3([String message = "3"]) : message_ = message;
   final String message_;
 }
 
 class Helper {
   Helper() : i = 0 { }
 
   int f1() {
     int j = 0;
     try {
       j = func();
-    } catch (MyException3 exception) {
+    } on MyException3 catch (exception) {
       i = i + 300;
       print(exception.message_);
-    } catch (MyException2 exception) {
+    } on MyException2 catch (exception) {
       i = i + 200;
       print(exception.message_);
-    } catch (MyException1 exception) {
+    } on MyException1 catch (exception) {
       i = i + 100;
       print(exception.message_);
     } finally {
       i = i + 1000;
     }
     return i;
   }
 
   // No catch in the same function for the type of exception being thrown
   // in the try block here. We expect the handler if checks to fall thru,
   // the finally block to run and an implicit rethrow to happen.
   int func() {
     i = 0;
     try {
       while (i < 10) {
         i++;
       }
       if (i > 0) {
         throw new MyException1("Test for MyException1 being thrown");
       }
-    } catch (MyException3 exception) {
+    } on MyException3 catch (exception) {
       i = 300;
       print(exception.message_);
-    } catch (MyException2 exception) {
+    } on MyException2 catch (exception) {
       i = 200;
       print(exception.message_);
     } finally {
       i = 800;
     }
     return i;
   }
   int i;
 }
 
 class Throw4Test {
   static testMain() {
     Expect.equals(1900, new Helper().f1());
   }
 }
 
 main() {
   Throw4Test.testMain();
 }