Remove custom expect.dart from Kernel tests

tests/kernel/unsorted/local_function_test.dart

 // Copyright (c) 2016, 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.
 
 // Tests of function expressions and function statements.
 
-import 'expect.dart';
+import 'package:expect/expect.dart';
 
 main() {
   var even;
   odd(n) => n > 0 && even(n - 1);
   even = (n) => n == 0 || odd(n - 1);
 
   Expect.isTrue(even(0));
   Expect.isTrue(!odd(0));
 
   Expect.isTrue(odd(1));
   Expect.isTrue(!even(1));
 
   Expect.isTrue(even(42));
   Expect.isTrue(!odd(42));
 
   Expect.isTrue(odd(101));
   Expect.isTrue(!even(101));
 }