Add tests for problem with newline encoding in multiline strings.

tests/language/multiline_newline_cr.dart

Index: tests/language/multiline_newline_cr.dart
diff --git a/tests/language/multiline_newline_cr.dart b/tests/language/multiline_newline_cr.dart
new file mode 100644
index 0000000000000000000000000000000000000000..c5c48bcda374334d14e5b229a30f434642afc821
--- /dev/null
+++ b/tests/language/multiline_newline_cr.dart
@@ -0,0 +1 @@
+// Copyright (c) 2015, 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 multiline_newline_cr;
const constantMultilineString = """
a
b
""";
var nonConstantMultilineString = """
a
b
""";