Do not show percentages when we don't know what they are in test progress indication.

tools/testing/dart/test_options.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.
 
 #library("test_options_parser");
 
 List<String> defaultTestSelectors =
     const ['samples', 'standalone', 'corelib', 'co19', 'language',
            'isolate', 'stub-generator', 'vm'];
 
@@ skipping 31 matching lines @@
         [ new _TestOptionSpecification(
               'mode',
               'Mode in which to run the tests',
               ['-m', '--mode'],
               ['all', 'debug', 'release'],
               'debug'),
           new _TestOptionSpecification(
               'component',
               'The component to test against',
               ['-c', '--component'],
-              ['most', 'vm', 'dartc', 'frog', 'frogsh', 'leg',
-               'chromium', 'dartium', 'frogium', 'webdriver'],
+              ['most', 'vm', 'dartc', 'frog', 'frogsh', 'leg'],
               'vm'),
           new _TestOptionSpecification(
               'architecture',
               'The architecture to run tests for',
               ['-a', '--arch'],
               ['all', 'ia32', 'x64', 'simarm'],
               'ia32'),
           new _TestOptionSpecification(
               'system',
               'The operating system to run tests on',
@@ skipping 101 matching lines @@
         // pattern.
         configuration.putIfAbsent('selectors', () => []);
         var patterns = configuration['selectors'];
         patterns.add(arg);
         continue;
       }
       // Find the option specification for the name.
       var spec = _getSpecification(name);
       if (spec == null) {
         print('Unknown test option $name');
-        return null;
+        exit(1);
       }
       // Parse the value for the option.
       if (spec.type == 'bool') {
         if (!value.isEmpty()) {
           print('No value expected for bool option $name');
-          return null;
+          exit(1);
         }
         configuration[spec.name] = true;
       } else if (spec.type == 'int') {
         try {
           configuration[spec.name] = Math.parseInt(value);
         } catch (var e) {
           print('Integer value expected for int option $name');
-          return null;
+          exit(1);
         }
       } else {
         assert(spec.type == 'string');
         for (var v in value.split(',')) {
           if (spec.values.lastIndexOf(v) == -1) {
             print('Unknown value ($v) for option $name');
-            return null;
+            exit(1);
           }
         }
         configuration[spec.name] = value;
       }
     }
     
     return _expandConfigurations(configuration);
   }
 
 
@@ skipping 159 matching lines @@
       if (option.keys.some((key) => key == name)) {
         return option;
       }
     }
     return null;
   }
 
 
   List<_TestOptionSpecification> _options;
 }