Update all occurrences of raw strings.

tests/language/string_escapes_test.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, 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.
 
 class StringEscapesTest {
 
   static testMain() {
     testDelimited();
     testFixed2();
     testFixed4();
     testEscapes();
@@ skipping 37 matching lines @@
 
   static testFixed4() {
     String str = "Foo\u0001Bar";
     Expect.equals(7, str.length);
     Expect.equals(1, str.charCodeAt(3));
     Expect.equals('B'.charCodeAt(0), str.charCodeAt(4));
   }
 
   static testLiteral() {
     String str = "\a\c\d\e\g\h\i\j\k\l\$\{\}\"";
-    Expect.equals(@'acdeghijkl${}"', str);
+    Expect.equals(r'acdeghijkl${}"', str);
   }
 }
 
 main() {
   StringEscapesTest.testMain();
 }