fix #28008, fix #28009 implement FutureOr<T>

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.
 
 [ $unchecked ]
 mirrors/redirecting_factory_different_type_test: SkipByDesign # Tests type checks.
 
 [ $compiler == dart2js ]
 async/schedule_microtask6_test: RuntimeError # global error handling is not supported. Issue 5958
 
@@ skipping 297 matching lines @@
 async/slow_consumer_test: Fail, Pass # Dartium JsInterop failure, dartbug.com/24460
 
 [ $compiler == dart2js && $runtime == safarimobilesim ]
 mirrors/mirrors_reader_test: SkipSlow # Times out. Issue 20806.
 mirrors/null_test: Fail # Issue 16831
 
 [ $compiler == dart2js && $runtime == jsshell ]
 async/schedule_microtask_test: Fail  # Preamble file does not correctly implement scheduleImmediate.
 
 [ $compiler == dartanalyzer || $compiler == dart2analyzer ]
-async/future_or_bad_type_test/00: MissingStaticWarning # Issue 28008
-async/future_or_bad_type_test/implements: MissingCompileTimeError # Issue 28008
-async/future_or_non_strong_test: StaticWarning # Issue 28008
-async/future_or_strong_test: StaticWarning # Issue 28008
-
 mirrors/generic_f_bounded_mixin_application_test: StaticWarning # Test Issue
 
 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/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/mirrors_nsm_test: StaticWarning, OK # Expect to trigger noSuchMethod.
 mirrors/mirrors_nsm_mismatch_test: StaticWarning, OK # Expect to trigger noSuchMethod.
 
@@ skipping 94 matching lines @@
 mirrors/typedef_deferred_library_test: Crash # Deferred loading
 mirrors/deferred_mirrors_update_test: Crash # Deferred loading
 mirrors/deferred_mirrors_metadata_test: Crash # Deferred loading
 mirrors/deferred_mirrors_metatarget_test: Crash # Deferred loading
 mirrors/load_library_test: Crash # Deferred loading
 
 [ $hot_reload ]
 mirrors/generic_bounded_test/02: Fail # Type equality - Issue 26869
 mirrors/generic_bounded_by_type_parameter_test/02: Fail # Type equality - Issue 26869
 async/timer_regress22626_test: Pass, RuntimeError # Timing dependent.