Fix a bug in printing of string literals with escape sequences.

testcases/input/stringliteral.dart

Index: testcases/input/stringliteral.dart
diff --git a/testcases/input/stringliteral.dart b/testcases/input/stringliteral.dart
new file mode 100644
index 0000000000000000000000000000000000000000..8e64de25ed1eb1e63133d44258ede8c9a2bd5ae0
--- /dev/null
+++ b/testcases/input/stringliteral.dart
@@ -0,0 +1,11 @@
+// Copyright (c) 2016, 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.
+var color = 'brown';
+var thing = 'lazy dog';
+var phrase = "The quick $color fox\njumped over the $thing.\n";
+var adjacent = '$color$color$color';
+var linebreaks = '$color\n$color\n$color';
+var other = '$color\n is \n$color';
+
+main() {}