Revert "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 e8a830fab491cad2f4123e61a19d01bda5485311..dfb71a54a8e1fdd55dd25b543da950e4e7e5dad3 100644
--- a/tests/standalone/io/skipping_dart2js_compilations_test.dart
+++ b/tests/standalone/io/skipping_dart2js_compilations_test.dart
@@ -14,11 +14,6 @@
  * 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';