Make some HTTP utility functions public

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.
 
 package/invalid_uri_test: Fail, OK # Fails intentionally
@@ skipping 56 matching lines @@
 io/test_runner_test: Fail # Library dart:uri removed.
 io/skipping_dart2js_compilations_test: Skip # Library dart:uri removed.
 
 
 # The dart:io library is created at build time from separate files, and
 # there is no language-spec compatible way to run unit tests on the private
 # members and methods of dart:io.
 # Dartc spots the misuse of 'part' directives in these unit tests.
 crypto/*: Skip  # dartc cannot parse dart:io unit tests.
 io/http_headers_test: Skip  # dartc cannot parse dart:io unit tests.
-io/http_date_test: Skip  # dartc cannot parse dart:io unit tests.
+io/http_cookie_date_test: Skip  # dartc cannot parse dart:io unit tests.
 io/url_encoding_test: Skip  # dartc cannot parse dart:io unit tests.
 io/http_parser_test: Skip  # dartc cannot parse dart:io unit tests.
 io/web_socket_protocol_processor_test: Skip  # dart:io unit test.
 
 io/process_exit_negative_test: Fail  # This is a compilation-time negative test.
 
 
 [ $compiler == dartanalyzer ]
 io/file_constructor_test: fail
-io/http_date_test: fail
+io/http_cookie_date_test: fail
 io/http_headers_test: fail
 io/http_parser_test: fail
 io/process_exit_negative_test: fail
 io/url_encoding_test: fail
 io/web_socket_protocol_processor_test: fail
 53bit_overflow_literal_test/01: fail, ok
 
 # Fails because checked-in dart executable is not up to date.
 io/test_runner_test: fail
 io/skipping_dart2js_compilations_test: fail
 
 
 [ $compiler == dart2analyzer ]
 io/file_constructor_test: fail
-io/http_date_test: fail
+io/http_cookie_date_test: fail
 io/http_headers_test: fail
 io/http_parser_test: fail
 io/process_exit_negative_test: fail
 io/url_encoding_test: fail
 io/web_socket_protocol_processor_test: fail
 53bit_overflow_literal_test/01: fail, ok
 
 # Fails because checked-in dart executable is not up to date.
 io/test_runner_test: fail
 io/skipping_dart2js_compilations_test: fail
@@ skipping 161 matching lines @@
 io/web_socket_test: Crash # Issue: 11207
 left_shift_bit_and_op_test: Fail # Issue: 11207
 typed_data_test: Crash # Issue: 11207
 
 
 [ $arch == mips ]
 *: Skip
 
 [ $arch == simmips ]
 *: Skip