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

tools/testing/dart/test_runner.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_runner");
 
 #import("status_file_parser.dart");
 #import("test_progress.dart");
 #import("test_suite.dart");
 
@@ skipping 308 matching lines @@
   }
 
   void _testListerDone() {
     _activeTestListers--;
     _checkDone();
   }
 
   void _checkDone() {
     // When there are no more active test listers ask for more work
     // from process queue users.
-    if (_activeTestListers == 0 &&
-        !_enqueueMoreWork(this) &&
-        _tests.isEmpty() &&
-        _numProcesses == 0) {
-      _terminateDartcBatchRunners();
-      _progress.allDone();
+    if (_activeTestListers == 0 && !_enqueueMoreWork(this)) {
+      _progress.allTestsKnown();
+      if (_tests.isEmpty() && _numProcesses == 0) {
+        _terminateDartcBatchRunners();
+        _progress.allDone();
+      }
     }
   }
 
   void _runTest(TestCase test) {
     _progress.testAdded();
     _tests.add(test);
     _tryRunTest();
   }
 
   void _terminateDartcBatchRunners() {
@@ skipping 32 matching lines @@
       if (test.executablePath.contains('compiler')) {
         _ensureDartcBatchRunnersStarted(test.executablePath);
         _getDartcBatchRunnerProcess().startTest(test);
       } else {
         new RunningProcess(test).start();
       }
       _numProcesses++;
     }
   }
 }