Add tests for reflecting on null and Null.

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/*: Skip
 mirrors/method_mirror_name_test: Fail # Issue 6335
 mirrors/method_mirror_properties_test: Fail # Issue 11861
 mirrors/method_mirror_returntype_test : Fail # Issue 11928
 mirrors/mirrors_test: Fail # TODO(ahe): I'm working on fixing this.
+mirrors/null_test : Fail # Issue 12129
 mirrors/library_uri_io_test: Skip # Not intended for dart2js as it uses dart:io.
 async/run_async3_test: Fail # _enqueueImmediate runs after Timer. http://dartbug.com/9002
 async/run_async4_test: Pass, Fail # no global exception handler in isolates. http://dartbug.com/9012
 async/run_async6_test: Fail # global error handling is not supported. http://dartbug.com/5958
 async/stream_controller_async_test: Fail, Pass # http://dartbug.com/11953
 
 
 [ $compiler == dart2js && ($runtime == d8) ]
 typed_data/byte_data_test: Fail, OK # d8 doesn't support DataView
 
@@ skipping 55 matching lines @@
 
 [ $runtime == opera && $system == windows]
 # TODO(efortuna): Investigate.
 async/timer_test: Fail, Pass
 
 [ $runtime == vm ]
 async/timer_not_available_test: Fail, OK # only meant to test when there is no way to
                                          # 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.
+mirrors/null_test: Fail # Issue 12128
 
 [ $runtime == vm || ($compiler == none && $runtime == drt) ]
 async/run_async3_test: Fail # _enqueueImmediate runs after Timer. http://dartbug.com/9001.
 mirrors/library_metadata_test: Fail # http://dartbug.com/10906
 mirrors/parameter_test: Fail # http://dartbug.com/11567
 mirrors/operator_test: Fail # http://dartbug.com/11944
 mirrors/local_isolate_test: Fail # http://dartbug.com/12026
 
 [ $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.
 async/run_async6_test: Fail # Issue 10910
 
 [ $compiler == none && $runtime == drt && $system == windows ]
 async/multiple_timer_test: Fail, Pass # See Issue 10982
 async/timer_test: Fail, Pass # See Issue 10982
 
 [ $arch == mips ]
 *: Skip
 
 [ $arch == simarm || $arch == arm ]
 typed_data/float32x4_two_arg_shuffle_test: Skip # Unimplemented instruction.
 typed_data/float32x4_transpose_test: Skip # Unimplemented instruction.
 
 [ $arch == simmips ]
 convert/chunked_conversion_utf88_test: Pass, Slow # Issue 12025.
 convert/streamed_conversion_json_utf8_decode_test: Pass, Slow