Do not compile tests for different browsers separately

tests/standalone/io/skipping_dart2js_compilations_test.dart

Index: tests/standalone/io/skipping_dart2js_compilations_test.dart
diff --git a/tests/standalone/io/skipping_dart2js_compilations_test.dart b/tests/standalone/io/skipping_dart2js_compilations_test.dart
index d01854185e8120cb9b7230c42756890f283e1bd8..6aa162ee15be5df59aa34468f7be87569b53e8c1 100644
--- a/tests/standalone/io/skipping_dart2js_compilations_test.dart
+++ b/tests/standalone/io/skipping_dart2js_compilations_test.dart
@@ -14,6 +14,11 @@
  * output (+deps file), dart application)
  */
 
+// TODO(kustermann): We need to change this test to include the shadow file
+// changes to CompilationCommand.
+// We can't do that right now, because we import testing scripts, which still
+// use the old binary.
+
 import 'package:expect/expect.dart';
 import 'dart:async';
 import 'dart:io';