Remove custom expect.dart from Kernel tests

tests/kernel/unsorted/try_finally_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.
 
-import 'expect.dart';
+import 'package:expect/expect.dart';
 
 testSimpleBreak() {
   var x = 1;
   while (true) {
     try {
       x++;
       break;
     } finally {
       x++;
       break;
@@ skipping 133 matching lines @@
   Expect.isTrue(testReturnFinally() == 42);
   Expect.isTrue(testNestedReturnFinally() == 42);
   Expect.isTrue(testReturnInsideLoop() == 42);
   Expect.isTrue(testStopContinueInsideLoop() == 42);
   Expect.isTrue(testStopBreakInsideLoop() == 42);
   Expect.isTrue(testStopBreakInsideLoop2() == 42);
   Expect.isTrue(testStopContinueInsideLoop() == 42);
   Expect.isTrue(testStopContinueInsideSwitch() == 42);
   Expect.isTrue(testStopContinueInsideSwitch2() == 42);
 }