Mark a test that has become flaky

tests/standalone/standalone.status

 # Copyright (c) 2013, 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.
 
 # WARNING:
 # Tests using the multitest feature where failure is expected should *also* be
 # listed in tests/lib/analyzer/analyze_tests.status without the "standalone"
 # prefix.
 
 io/raw_socket_test: Pass, RuntimeError # Issue 28288
+io/http_close_test: Pass, RuntimeError # Issue 28380
 
 packages_file_test: Skip # Issue 26715
 packages_file_test/none: Skip   # contains no tests.
 
 package/invalid_uri_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/packages_file_strange_formatting/empty_package_dir_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/empty_packages_file/empty_packages_file_discovery_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/empty_packages_file/empty_packages_file_option_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/invalid/invalid_package_name_test: RuntimeError, CompileTimeError # Errors intentionally
 package/scenarios/invalid/same_package_twice_test.dart: RuntimeError, CompileTimeError # Errors intentionally
 
 issue14236_test: Pass # Do not remove this line. It serves as a marker for Issue 14516 comment #4.
 
-[ ($runtime != vm && $runtime != dart_precompiled) && ($runtime != drt || $compiler != none)) ]
+[ ($runtime != vm && $runtime != dart_precompiled) && ($runtime != drt || $compiler != none) ]
 no_assert_test: Fail, OK # This is testing a vm flag.
 env_test: Skip # This is testing a vm command line parsing scenario.
 
 [ $runtime == vm || $runtime == dart_precompiled ]
 package/package_isolate_test: Fail # Issue 12474
 io/observatory_test: Fail
 package/scenarios/invalid/same_package_twice_test: Pass # Issue 24119
 
 [ ($runtime == vm || $runtime == dart_precompiled) && $checked ]
 # These tests have type errors on purpose.
@@ skipping 347 matching lines @@
 io/directory_list_nonexistent_test: Fail # Issue 28350
 
 io/stdout_bad_argument_test: Fail # Issue 28353
 io/file_blocking_lock_test: Fail # Issue 28353
 
 io/process_sync_test: RuntimeError
 io/signals_test: RuntimeError
 io/regress_7191_test: RuntimeError
 io/named_pipe_script_test: RuntimeError
 io/http_server_close_response_after_error_test: RuntimeError