Revert "Remove Expect from core library."

tests/standalone/io/process_non_ascii_test.dart

Index: tests/standalone/io/process_non_ascii_test.dart
diff --git a/tests/standalone/io/process_non_ascii_test.dart b/tests/standalone/io/process_non_ascii_test.dart
index 020b07e075f390490dfa14b3bafcdb3209a6d468..88291bede5b7095afe6db490baab4b2baa335c6d 100644
--- a/tests/standalone/io/process_non_ascii_test.dart
+++ b/tests/standalone/io/process_non_ascii_test.dart
@@ -2,7 +2,6 @@
 // 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.
 
-import "package:expect/expect.dart";
 import 'dart:io';
 import 'dart:isolate';
 
@@ -18,9 +17,7 @@ main() {
 import 'dart:io';
 
 main() {
-  if ('æøå' != new File('æøå.txt').readAsStringSync()) {
-    throw new RuntimeError("not equal");
-  }
+  Expect.equals('æøå', new File('æøå.txt').readAsStringSync());
 }
 """);
   var nonAsciiTxtFile = new File('${nonAsciiDir.path}/æøå.txt');