Disable wrapping of Firefox/Windows dart2js tests.

dart/tools/testing/dart/test_suite.dart

Index: dart/tools/testing/dart/test_suite.dart
diff --git a/dart/tools/testing/dart/test_suite.dart b/dart/tools/testing/dart/test_suite.dart
index dd639df668a09bff92ad44321dcf5f705b5e2643..61a4700d9bc3d78b0e33050d7e36b46deac75127 100644
--- a/dart/tools/testing/dart/test_suite.dart
+++ b/dart/tools/testing/dart/test_suite.dart
@@ -422,11 +422,6 @@ class StandardTestSuite implements TestSuite {
       enqueueStandardTest(info, testName, expectations);
     } else if (TestUtils.isBrowserRuntime(configuration['runtime'])) {
       bool isWrappingRequired = configuration['compiler'] != 'dart2js';
-      if (configuration['runtime'] == 'ff' &&
-          Platform.operatingSystem == 'windows') {
-        // TODO(ahe): Investigate why this doesn't work on Windows.
-        isWrappingRequired = true;
-      }
       enqueueBrowserTest(info, testName, expectations, isWrappingRequired);
     } else {
       enqueueStandardTest(info, testName, expectations);