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

tests/corelib/string_base_vm_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 class 'StringBase' (currently VM specific).
 
 #library("StringBaseTest.dart");
 #import("dart:coreimpl");
 
 
 class StringBaseTest {
@@ skipping 30 matching lines @@
     for (int i = 0; i < a.length; i++) {
       a[i] = s.charCodeAt(i);
       ga.add(s.charCodeAt(i));
     }
     String s2 = StringBase.createFromCharCodes(a);
     Expect.equals(s, s2);
     String s3 = StringBase.createFromCharCodes(ga);
     Expect.equals(s, s3);
     try {
       String s4 = new String.fromCharCodes([0.0]);
-    } catch (IllegalArgumentException ex) {
+    } on IllegalArgumentException catch (ex) {
       exception_caught = true;
     }
     Expect.equals(true, exception_caught);
     exception_caught = false;
     try {
       String s4 = new String.fromCharCodes([-1]);
-    } catch (IllegalArgumentException ex) {
+    } on IllegalArgumentException catch (ex) {
       exception_caught = true;
     }
     Expect.equals(true, exception_caught);
   }
 
   static testSubstring() {
     String s = "Hello World";
     Expect.equals("World", s.substring(6, s.length));
     Expect.equals("", s.substring(8, 8));
     bool exception_caught = false;
     try {
       s.substring(5, 12);
-    } catch (IndexOutOfRangeException ex) {
+    } on IndexOutOfRangeException catch (ex) {
       exception_caught = true;
     }
     Expect.equals(true, exception_caught);
     exception_caught = false;
     try {
       s.substring(5, 4);
-    } catch (IndexOutOfRangeException ex) {
+    } on IndexOutOfRangeException catch (ex) {
       exception_caught = true;
     }
     Expect.equals(true, exception_caught);
   }
 
   static void testMain() {
     testSubstringMatches();
     testInterpolation();
     testCreation();
     testSubstring();
   }
 }
 
 main() {
   StringBaseTest.testMain();
 }