Remove custom expect.dart from Kernel tests

tests/kernel/unsorted/try_finally_test.dart

Index: tests/kernel/unsorted/try_finally_test.dart
diff --git a/tests/kernel/unsorted/try_finally_test.dart b/tests/kernel/unsorted/try_finally_test.dart
index 3eddd4ff7239c2329291dd461ab9c85264faa653..db3069b0f0467c59dbd5f0305dbd56f5702f5039 100644
--- a/tests/kernel/unsorted/try_finally_test.dart
+++ b/tests/kernel/unsorted/try_finally_test.dart
@@ -2,7 +2,7 @@
 // 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 'expect.dart';
+import 'package:expect/expect.dart';
 
 testSimpleBreak() {
   var x = 1;