Fix Unicode issues in dart2js and dart2dart.

tests/corelib/string_from_list_test.dart

Index: tests/corelib/string_from_list_test.dart
diff --git a/tests/corelib/string_from_list_test.dart b/tests/corelib/string_from_list_test.dart
index acd0f5c22eef79e4cfea4391a9639fbfa63c625d..ec435921ece5c07616432cc26016447558d7de02 100644
--- a/tests/corelib/string_from_list_test.dart
+++ b/tests/corelib/string_from_list_test.dart
@@ -9,11 +9,16 @@ class StringFromListTest {
     Expect.equals("", new String.fromCharCodes(const []));
     Expect.equals("AB", new String.fromCharCodes([65, 66]));
     Expect.equals("AB", new String.fromCharCodes(const [65, 66]));
+    Expect.equals("Ærø", new String.fromCharCodes(const [0xc6, 0x72, 0xf8]));
+    Expect.equals("\u{1234}", new String.fromCharCodes([0x1234]));
+    Expect.equals("\u{12345}*", new String.fromCharCodes([0x12345, 42]));
     Expect.equals("", new String.fromCharCodes(new List()));
-    var a = new List();
-    a.add(65);
-    a.add(66);
-    Expect.equals("AB", new String.fromCharCodes(a));
+    {
+      var a = new List();
+      a.add(65);
+      a.add(66);
+      Expect.equals("AB", new String.fromCharCodes(a));
+    }
   }
 }