Use new try-catch syntax in runtime/, tools/, and utils/.

runtime/bin/http_utils.dart

 // Copyright (c) 2012, 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.
 
 class _HttpUtils {
   static String decodeUrlEncodedString(String urlEncoded) {
     // First check the string for any encoding.
     int index = 0;
     bool encoded = false;
     while (!encoded && index < urlEncoded.length) {
@@ skipping 194 matching lines @@
       if (separator.length > 0) {
         pos = date.indexOf(separator, index);
       } else {
         pos = date.length;
       }
       String tmp = date.substring(index, pos);
       index = pos + separator.length;
       try {
         int value = parseInt(tmp);
         return value;
-      } catch (FormatException e) {
+      } on FormatException catch (e) {
         throw new HttpException("Invalid HTTP date $date");
       }
     }
 
     void expectEnd() {
       if (index != date.length) {
         throw new HttpException("Invalid HTTP date $date");
       }
     }
 
@@ skipping 20 matching lines @@
       hours = expectNum(":");
       minutes = expectNum(":");
       seconds = expectNum(" ");
       expect("GMT");
     }
     expectEnd();
     return new Date(
         year, month + 1, day, hours, minutes, seconds, 0, isUtc: true);
   }
 }