Revert "Remove test retrying for Safari, in test scripts."

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 2606 matching lines @@
   Future cleanup() => new Future.value();
 
   Future<CommandOutput> runCommand(node, ProcessCommand command, int timeout) {
     assert(node.dependencies.length == 0);
     return new Future.value(_archive.outputOf(command));
   }
 }
 
 bool shouldRetryCommand(CommandOutput output) {
   var command = output.command;
+  // We rerun tests on Safari because 6.2 and 7.1 are flaky. Issue 21434.
+  if (command is BrowserTestCommand &&
+      command.retry &&
+      command.browser == 'safari' &&
+      output is BrowserControllerTestOutcome &&
+      output._rawOutcome != Expectation.PASS) {
+    return true;
+  }
+
   if (!output.successful) {
     List<String> stdout, stderr;
 
     decodeOutput() {
       if (stdout == null && stderr == null) {
         stdout = decodeUtf8(output.stderr).split("\n");
         stderr = decodeUtf8(output.stderr).split("\n");
       }
     }
 
@@ skipping 309 matching lines @@
     }
   }
 
   void eventAllTestsDone() {
     for (var listener in _eventListener) {
       listener.allDone();
     }
     _allDone();
   }
 }