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

utils/css/css.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.
 
 #library('css');
 
 #import('dart:math', prefix: 'Math');
 #import("../lib/file_system.dart");
 #import('../lib/file_system_memory.dart');
 
@@ skipping 44 matching lines @@
       cssExpression));
   String output = "";
   String prettyTree = "";
   try {
     var tree = parser.parseTemplate();
     if (tree != null) {
       prettyTree = tree.toDebugString();
       Validate.template(tree.selectors, cssworld);
       output = prettyTree;
     }
-  } catch (var e) {
+  } catch (e) {
     String error = e.toString();
     output = "$error\n$prettyTree";
     throw e;
   }
 
   return output;
 }