Consider tests as flaky if it contains more than one marker (which can occur when running the test)

tools/testing/dart/test_runner.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.
 
 /**
  * Classes and methods for executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 529 matching lines @@
 
   bool get usesWebDriver => TestUtils.usesWebDriver(configuration['runtime']);
 
   bool get isFlaky {
       if (expectedOutcomes.contains(SKIP) ||
           expectedOutcomes.contains(SKIP_BY_DESIGN)) {
         return false;
       }
 
       var flags = new Set.from(expectedOutcomes);
-      flags..remove(TIMEOUT)
+      flags..remove(OK)
            ..remove(SLOW);
-      return flags.contains(PASS) && flags.length > 1;
+      return flags.length > 1;
   }
 
   bool get isFinished {
     return !lastCommandOutput.successful ||
            commands.length == commandOutputs.length;
   }
 }
 
 
 /**
@@ skipping 1593 matching lines @@
     }
   }
 
   void eventAllTestsDone() {
     for (var listener in _eventListener) {
       listener.allDone();
     }
     _allDone();
   }
 }