Mark lib/mirrors/hierarchy_invariants_test as slow on drt.

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.
 
 [ $csp ]
 mirrors/delegate_test: RuntimeError # Issue 13864
 
 [ $compiler == dart2js ]
 async/schedule_microtask3_test: RuntimeError # _enqueueImmediate runs after Timer. http://dartbug.com/9002
 async/schedule_microtask4_test: Pass, RuntimeError # no global exception handler in isolates. http://dartbug.com/9012
@@ skipping 171 matching lines @@
 async/timer_not_available_test: SkipByDesign # only meant to test when there is no way to implement timer (currently only in d8)
 
 [ $compiler == none && ( $runtime == drt || $runtime == dartium ) ]
 mirrors/immutable_collections_test: Fail # Issue 11857, Issue 14321
 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/schedule_microtask6_test: Fail # Issue 10910
 async/schedule_microtask4_test: Fail # Issue 13921
 platform/isolate_test: Skip # Issue 14444
 
+[ $compiler == none && $runtime == drt && $mode == debug ]
+mirrors/hierarchy_invariants_test: Pass, Slow # Issue 14449
+
 [ $compiler == none && $runtime == drt && $system == windows ]
 async/multiple_timer_test: Fail, Pass # See Issue 10982
 async/timer_test: Fail, Pass # See Issue 10982
 
 [ $arch == simmips || $arch == mips ]
 convert/chunked_conversion_utf88_test: Pass, Slow # Issue 12025.
 convert/streamed_conversion_json_utf8_decode_test: Pass, Slow
 
 [ $arch == simarm ]
 convert/chunked_conversion_utf88_test: Pass, Slow # Issue 12644.
@@ skipping 24 matching lines @@
 mirrors/generic_interface_test/none: Fail # Inexpressible in multitest
 mirrors/type_variable_owner_test/none: Fail # Issue 14356
 
 [ $compiler == none && $runtime == dartium ]
 async/schedule_microtask5_test: Pass, Timeout # Issue 13719: Please triage this failure.
 async/timer_cancel2_test: Pass, Timeout # Issue 13719: Please triage this failure.
 
 [ ($compiler != none && $runtime != none) || ($compiler == none && ($runtime != dartium && $runtime != drt)) ]
 async/schedule_microtask_test: Fail # Issue 9001, Issue 9002