Roll Observatory packages and add a roll script

packages/intl/test/message_extraction/embedded_plural_text_before_test.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+library embedded_plural_text_before_test;
+
+import "failed_extraction_test.dart";
+import "package:unittest/unittest.dart";
+
+main() {
+  test("Expect failure because of embedded plural with text before it", () {
+    var files = ['embedded_plural_text_before.dart'];
+    runTestWithWarnings(
+        warningsAreErrors: true,
+        expectedExitCode: 1,
+        embeddedPlurals: false,
+        sourceFiles: files);
+  });
+}