Make TypedefMirror a direct descendant of TypeMirror.

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 ]
 math/double_pow_test: RuntimeError
 math/low_test: RuntimeError
 math/random_test: RuntimeError
 mirrors/closure_mirror_find_in_context_test: Fail # Issue 6490
 mirrors/equality_test/02: RuntimeError # Issue 12333
@@ skipping 126 matching lines @@
                                          # implement timer (currently only in d8)
 async/timer_isolate_test: Skip # See Issue 4997
 mirrors/native_class_test: Fail, OK # This test is meant to run in a browser.
 
 [ $runtime == vm || ($compiler == none && $runtime == drt) ]
 async/run_async3_test: Fail # _enqueueImmediate runs after Timer. http://dartbug.com/9001.
 mirrors/hierarchy_test: Fail # TODO(ahe): This test is slightly broken. http://dartbug.com/12464
 mirrors/mixin_test/01: Fail, OK # TODO(ahe): Slight broken test to ensure test coverage on dart2js.
 mirrors/typedef_test/01: Fail, OK # Incorrect dart2js behavior.
 mirrors/closures_test/01: Fail, OK # Incorrect dart2js behavior.
+mirrors/typevariable_mirror_metadata_test/none: RuntimeError # Issue 12282
 
 [ $compiler == none && $runtime == drt ]
 async/timer_isolate_test: Skip # See Issue 4997
 async/timer_not_available_test: Skip # only meant to test when there is no way to
                                      # implement timer (currently only in d8)
 mirrors/library_uri_io_test: Skip # Not intended for drt as it uses dart:io.
 mirrors/local_isolate_test: Skip # http://dartbug.com/12188
 async/run_async6_test: Fail # Issue 10910
 
 [ $compiler == none && $runtime == drt && $system == windows ]
@@ skipping 15 matching lines @@
 async/stream_controller_async_test: Pass, Fail # Issue 13608
 
 [ $compiler == dartanalyzer ]
 mirrors/typedef_test/none: Fail # Issue 13093
 mirrors/generics_test/none: Fail # Issue 13432
 mirrors/invoke_named_test/none: Fail # http://dartbug.com/13612
 
 mirrors/parameter_metadata_test: Fail # Issue 13510
 mirrors/method_mirror_returntype_test: Fail # Issue 13510
 mirrors/function_type_mirror_test: Fail # Issue 13510
-mirrors/typevariable_mirror_metadata_test: Fail # Issue 13510
+mirrors/typevariable_mirror_metadata_test/none: Fail # Issue 13510
 
 [ $compiler == dart2analyzer ]
 mirrors/typedef_test/none: Fail # Issue 13093
 mirrors/generics_test/none: Fail # Issue 13432
 mirrors/invoke_named_test/none: Fail # http://dartbug.com/13612
 
 mirrors/parameter_metadata_test: Fail # Issue 13510
 mirrors/method_mirror_returntype_test: Fail # Issue 13510
 mirrors/function_type_mirror_test: Fail # Issue 13510
-mirrors/typevariable_mirror_metadata_test: Fail # Issue 13510
+mirrors/typevariable_mirror_metadata_test/none: Fail # Issue 13510
 
 [ $compiler == none && $runtime == dartium ]
 async/run_async3_test: Fail # Issue 13719: Please triage this failure.
 async/run_async4_test: Fail # Issue 13719: Please triage this failure.
 async/run_async6_test: Fail # Issue 13719: Please triage this failure.
 async/timer_not_available_test: Fail # Issue 13719: Please triage this failure.
 mirrors/closures_test/01: Fail # Issue 13719: Please triage this failure.
 mirrors/hierarchy_test: Fail # Issue 13719: Please triage this failure.
 mirrors/library_uri_io_test: Fail # Issue 13719: Please triage this failure.
 mirrors/local_isolate_test: Fail # Issue 13719: Please triage this failure.
 mirrors/mixin_test/01: Fail # Issue 13719: Please triage this failure.
 mirrors/typedef_test/01: Fail # Issue 13719: Please triage this failure.