Rip out the last dart:io dependency from pkg/http.

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 187 matching lines @@
 analyzer/test/generated/element_test: Fail, OK # Uses dart:io.
 analyzer/test/generated/element_test: Fail, OK # Uses dart:io.
 analyzer/test/generated/parser_test: Fail, OK # Uses dart:io.
 analyzer/test/generated/resolver_test: Fail, OK # Uses dart:io.
 analyzer/test/generated/resolver_test: Fail, OK # Uses dart:io.
 analyzer/test/options_test: Fail, OK # Uses dart:io.
 analyzer/test/parse_compilation_unit_test: Fail, OK # Uses dart:io.
 analyzer/test/services/formatter_test: Fail, OK # Uses dart:io.
 barback/test/*: Fail, OK # Uses dart:io.
 code_transformers/test/*: Skip # Uses dart:io.
-http/test/client_test: Fail, OK # Uses dart:io.
-http/test/http_test: Fail, OK # Uses dart:io.
-http/test/mock_client_test: Fail, OK # Uses dart:io.
-http/test/multipart_test: Fail, OK # Uses dart:io.
-http/test/request_test: Fail, OK # Uses dart:io.
-http/test/response_test: Fail, OK # Uses dart:io.
-http/test/streamed_request_test: Fail, OK # Uses dart:io.
+http/test/io/*: Fail, OK # Uses dart:io.
 http_parser/test/web_socket_test: Fail, OK # Uses dart:io
 http_server/test/*: Fail, OK # Uses dart:io.
 intl/test/date_time_format_file_even_test: Fail, OK # Uses dart:io.
 intl/test/date_time_format_file_odd_test: Fail, OK # Uses dart:io.
 intl/test/find_default_locale_standalone_test: Fail, OK # Uses dart:io.
 intl/test/message_extraction/examples_parsing_test: Fail, OK # Users dart:io
 intl/test/message_extraction/failed_extraction_test: Fail, OK # Users dart:io
 intl/test/message_extraction/message_extraction_test: Fail, OK # Uses dart:io.
 intl/test/message_extraction/really_fail_extraction_test: Fail, OK # Users dart:io
 oauth2/test/authorization_code_grant_test: Fail, OK # Uses dart:io.
@@ skipping 82 matching lines @@
 
 [ $runtime == vm ]
 # Skip tests on the VM if the package depends on dart:html
 custom_element: Skip
 template_binding: Skip
 mutation_observer: Skip
 polymer_expressions/test/syntax_test: Skip
 polymer_expressions/test/globals_test: Skip
 polymer_expressions/test/bindings_test: Skip
 third_party/html5lib/test/browser/browser_test: Skip
+http/test/html/*: Skip
 
 [ $runtime == safari || $ie ]
 polymer_expressions/test/globals_test: Fail # Issue 16568
 polymer_expressions/test/bindings_test: Fail # Issue 16568
 
 [ $browser ]
 docgen/test/*: Skip  # Uses dart:io
 scheduled_test/test/scheduled_server_test: Skip # Uses dart:io
 
 [ $browser || $runtime == vm ]
@@ skipping 21 matching lines @@
 third_party/angular_tests/browser_test/core/scope: Skip # Requires checked mode.
 third_party/angular_tests/browser_test/core/zone: Skip # Requires checked mode.
 third_party/angular_tests/browser_test/directive/ng_repeat: Skip # Issue 17152
 third_party/angular_tests/browser_test/change_detection/dirty_checking_change_detector: Skip # Issue 17152
 
 [ $use_repository_packages ]
 analyzer/test/*: PubGetError
 
 [ $runtime == ie9 ]
 polymer: Pass, Fail, Timeout # Issue 16717
+
+[ $runtime == drt ]
+http/test/html/client_test: Skip # Issue 18566