Introduce class TypeRef in the VM to fully support recursive types.

pkg/pkg.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.
 
 # Don't run any test-like files that show up in packages directories. It
 # shouldn't be necessary to run "pub install" in these packages, but if you do
 # it shouldn't break the tests.
 */packages/*/*: Skip
 */*/packages/*/*: Skip
 */*/*/packages/*/*: Skip
@@ skipping 236 matching lines @@
 # not minified.
 unittest/test/*_minified_test: Skip # DO NOT COPY THIS UNLESS YOU WORK ON DART2JS
 
 [ $arch == mips ]
 *: Skip  # Issue 13650
 
 [ $arch == arm ]
 *: Skip  # Issue 13624
 
 [ $arch == simarm || $arch == simmips ]
-barback/test/too_many_open_files_test: Slow, RuntimeError # 14220
+barback/test/too_many_open_files_test: Skip # 14220
 third_party/html5lib/test/tokenizer_test: Pass, Slow
 
 # Skip serialization test that explicitly has no library declaration in the
 # test on Dartium, which requires all tests to have a library.
 [ $compiler == none && ( $runtime == dartium || $runtime == drt ) ]
 serialization/test/no_library_test: Skip # Expected Failure
 serialization/test/serialization_test: Fail # 13921
 unittest/test/unittest_async_exception_test: Fail # 13921
 unittest/test/unittest_async_setup_teardown_test: Fail # 13921
 unittest/test/unittest_completion_test: Fail # 13921
@@ skipping 63 matching lines @@
 unittest/test/mock_test: StaticWarning, OK # testing unimplemented members
 
 [ $runtime == vm && ($system == windows || $system == macos) ]
 watcher/test/*/linux_test: Skip
 
 [ $runtime == vm && ($system == windows || $system == linux) ]
 watcher/test/*/mac_os_test: Skip
 
 [ $runtime == vm && $system == macos ]
 watcher/test/directory_watcher/mac_os_test: Pass, Fail # Issue 15024