Remove test retrying for Safari, in test scripts.

tools/testing/dart/test_runner.dart

Index: tools/testing/dart/test_runner.dart
diff --git a/tools/testing/dart/test_runner.dart b/tools/testing/dart/test_runner.dart
index 1bdf34e2b4d22e29967d886c11ae23140e30d9e3..2b1ef3824318db9a5f26037c208a366e3bb8811d 100644
--- a/tools/testing/dart/test_runner.dart
+++ b/tools/testing/dart/test_runner.dart
@@ -2622,15 +2622,6 @@ class ReplayingCommandExecutor implements CommandExecutor {
 
 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;