Migrate language/arithmetic2_test ... language/async_await_syntax_test.

tests/language_2/assertion_test.dart

 // Copyright (c) 2011, 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.
-// VMOptions=--enable_type_checks
-//
+// VMOptions=--enable_type_checks --enable_asserts
+
 // Dart test program testing assert statements.
 
 import "package:expect/expect.dart";
 
 testTrue() {
   int i = 0;
   try {
     assert(true);
   } on AssertionError catch (error) {
     i = 1;
@@ skipping 90 matching lines @@
   Expect.equals('hi', testMessage(() => false, 'hi').message);
 
   // These errors do not have the message because boolean conversion failed.
   Expect.equals(null, testMessage(null, 1234).message);
   Expect.equals(null, testMessage(null, 'hi').message);
   Expect.equals(null, testMessage(() => null, 1234).message);
   Expect.equals(null, testMessage(() => null, 'hi').message);
   Expect.isTrue("${testMessage(42, 1234)}".contains('boolean expression'));
   Expect.isTrue("${testMessage(() => 1, 1234)}".contains('boolean expression'));
 }