Ensure a class is finalized before attempting any reflective invocation on it.

tests/lib/lib.status

 # 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.
 
 [ $compiler == dart2js && $checked && $runtime == ie9 ]
 convert/ascii_test: Skip # http://dartbug.com/15498
 convert/streamed_conversion_json_utf8_encode_test: Skip # http://dartbug.com/15498
 convert/streamed_conversion_utf8_encode_test: Skip # http://dartbug.com/15498
 
 [ $csp ]
@@ skipping 181 matching lines @@
 [ $runtime == opera ]
 async/multiple_timer_test: Pass, Fail # Probably issue 14734
 
 [ $runtime == opera && $system == windows]
 # TODO(efortuna): Investigate.
 async/timer_test: Fail, Pass
 
 [ $runtime == vm ]
 async/timer_not_available_test: Fail, OK
 mirrors/native_class_test: Fail, OK # This test is meant to run in a browser.
-mirrors/syntax_error_test/01: Fail # Issue 15886
 
 [ $compiler == none  ]
 mirrors/hierarchy_test: Fail # TODO(ahe): This test is slightly broken. http://dartbug.com/12464
 mirrors/mixin_application_test/01: Fail, OK # TODO(ahe): Slight broken test to ensure test coverage on dart2js.
 mirrors/intercepted_object_test: Fail, OK # TODO(ahe): Slight broken test to ensure test coverage on dart2js.
 mirrors/typedef_test/01: Fail, OK # Incorrect dart2js behavior.
 
 mirrors/generic_local_function_test: RuntimeError # Issue 14913
 mirrors/symbol_validation_test: RuntimeError # Issue 13596
 mirrors/synthetic_accessor_properties_test/none: RuntimeError # Issue 14632
@@ skipping 44 matching lines @@
 
 mirrors/redirecting_factory_test/01: StaticWarning # test issue X, The return type 'Class<T2, T1>' of the redirected constructor is not assignable to 'Class<T1, T2>'
 mirrors/redirecting_factory_test/none: StaticWarning # test issue X, The return type 'Class<T2, T1>' of the redirected constructor is not assignable to 'Class<T1, T2>
 
 mirrors/fake_function_without_call_test: StaticWarning, OK # Implements Function without defining call.
 mirrors/find_in_context_fake_function_test: StaticWarning, OK # Implements Function without defining call.
 mirrors/immutable_collections_test: StaticWarning, OK # Expect failure for any type of Iterable.
 mirrors/inference_and_no_such_method_test: StaticWarning, OK # Expect to trigger noSuchMethod.
 mirrors/repeated_private_anon_mixin_app_test: StaticWarning, OK # Intentional library name conflict.
 mirrors/removed_api_test: StaticWarning, OK # Deliberately refers to undeclared members.