Add HTML test with two dart scripts on one page.

tests/html/two_scripts_test_first.dart

Index: tests/html/two_scripts_test_first.dart
diff --git a/tests/language/metadata_self_test.dart b/tests/html/two_scripts_test_first.dart
similarity index 57%
copy from tests/language/metadata_self_test.dart
copy to tests/html/two_scripts_test_first.dart
index 434cc38a0a0c2cc3aa81953b34b4cbdb7cd8abee..1813aa5d91604c4d17887357930d66a2a291373b 100644
--- a/tests/language/metadata_self_test.dart
+++ b/tests/html/two_scripts_test_first.dart
@@ -2,13 +2,14 @@
 // 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.
 
-// Test that metadata refer to the annotated declaration.
+library TwoScriptsTestFirst;
+import 'dart:html';
 
-@Foo()
-class Foo {
-  const Foo();
+aGlobalFunction() {
+  window.postMessage('first_global', '*');

[sigurdm, 2014/11/18 08:19:55]

Why do we have a "local" and a "global" message? What is the difference? Do we
expect cases where one fails and the other succeeds?

[Bill Hesse, 2014/11/18 09:16:47]

I just made this up.  I tried to think of something worth testing about two
scripts, and all I could think of was globals.  It can be removed if you want.

 }
 
 main() {
-  Foo f = const Foo();
+  window.postMessage('first_local', '*');
+  aGlobalFunction();
 }