Revert "Remove Expect from core library."

tests/language/bad_named_parameters_test.dart

 // Copyright (c) 2012, 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.
 // Dart test program for testing bad named parameters.
 
-import "package:expect/expect.dart";
-
 
 class BadNamedParametersTest {
 
   int f42(int a, {int b: 20, int c: 30}) {
     return 100*(100*a + b) + c;
   }
 
   int f52(int a, {int b: 20, int c, int d: 40}) {
     return 100*(100*(100*a + b) + (c == null ? 0 : c)) + d;
   }
@@ skipping 42 matching lines @@
     } on NoSuchMethodError catch (e) {
       caught = true;
     }
     Expect.equals(true, caught);
   }
 }
 
 main() {
   BadNamedParametersTest.testMain();
 }