Updated sanitizeCategory to better account for category names.

tools/gardening/lib/src/util.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
 
@@ skipping 90 matching lines @@
   if (argResults['cache'] != null) {
     cache.base = Uri.base.resolve('${argResults['cache']}/');
   }
   if (argResults['no-cache']) {
     cache.base = null;
   }
 }
 
 /// Strips un-wanted characters from string [category] from CBE json.
 String sanitizeCategory(String category) {
-  // Category name starts with either two or three numbers and
-  // end with |all. Instead of doing any fancy regular-expr,
-  // we just test if third char is a number.
-  return category.substring(
-      category.codeUnitAt(2) <= 64 ? 3 : 2, category.length - 4);
+  var reg = new RegExp(r"^[0-9]+(.*)\|all$");
+  var match = reg.firstMatch(category);
+  return match != null ? match.group(1) : category;
 }