Add List.first.

tests/corelib/list_first_test.dart

Index: tests/corelib/list_first_test.dart
diff --git a/tests/language/field_type_check2_test.dart b/tests/corelib/list_first_test.dart
similarity index 54%
copy from tests/language/field_type_check2_test.dart
copy to tests/corelib/list_first_test.dart
index 80925f4f7d4d307073a8c4634a9bd1b90c2e0c41..cdd718be90ee742f5e1a610a03ebca1a280e0129 100644
--- a/tests/language/field_type_check2_test.dart
+++ b/tests/corelib/list_first_test.dart
@@ -2,19 +2,17 @@
 // 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 A {
-  A a;
-
-  bar(c) {
-    c.a = 2; /// 01: dynamic type error
+void test(List list) {
+  if (list.isEmpty) {
+    Expect.throws(() => list.first, (e) => e is RangeError);
+  } else {
+    Expect.equals(list[0], list.first);
   }
 }
 
-class B {
-  int a;
-}
-
 main() {
-  new A().bar(new A()); /// 01: continued
-  new A().bar(new B());
+  test([1, 2, 3]);
+  test(const ["foo", "bar"]);
+  test([]);
+  test(const []);
 }