- Allow string interpolation in constant strings.

tests/language/src/StringInterpolation8Test.dart

Index: tests/language/src/StringInterpolation8Test.dart
===================================================================
--- tests/language/src/StringInterpolation8Test.dart	(revision 5361)
+++ tests/language/src/StringInterpolation8Test.dart	(working copy)
@@ -2,13 +2,13 @@
 // 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.
 //
-// Disallow assignment of string interpolation to a static final field
+// Allow assignment of string interpolation to a static final field
 
 class A {
   static final x = 1;
-  static final y = "Two is greater than ${x}";  // ERROR: String interpolation
+  static final y = "Two is greater than ${x}";
 }
 
 main() {
-  var a = A.y;
+  Expect.identical("Two is greater than 1", A.y);
 }