fix list_test for strong mode, and fix DDC List constructors

tests/corelib_2/growable_list_test.dart

Index: tests/corelib_2/growable_list_test.dart
diff --git a/tests/corelib_2/growable_list_test.dart b/tests/corelib_2/growable_list_test.dart
index 355d9cc60ef530dd35c6268b3325a1701fb15d10..79d53150d4ef8bded13c982ac25224df3a0197e7 100644
--- a/tests/corelib_2/growable_list_test.dart
+++ b/tests/corelib_2/growable_list_test.dart
@@ -165,20 +165,4 @@ void testConcurrentModification() {
     l.addAll(ci);
     Expect.listEquals(new List.generate(500, (x) => x), l, "cm6");
   }
-
-  {
-    // Adding to yourself.
-    var l = [1];
-    Expect.throws(() {
-      l.addAll(l);
-    }, (e) => e is ConcurrentModificationError, "cm7");
-  }
-
-  {
-    // Adding to yourself.
-    var l = [1, 2, 3];
-    Expect.throws(() {
-      l.addAll(l);
-    }, (e) => e is ConcurrentModificationError, "cm8");
-  }
 }