Fix OAuth2 tests, and disable them on non-dart:io platforms.

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.
 
 # Run this test manually to verify that the fixnum library produces
 # the same results as native ints on a set of directed and random inputs.
 # Skip it when running automated tests because it times out.  This
 # test only makes sense on runtimes that support 64-bit integer
 # arithmetic natively, i.e., the VM.
 fixnum/test/int_64_vm_test: Skip
 
 [$compiler == dart2dart]
 *: Skip
 
 # Don't compiile tests that use dart:io to JS
 [ $compiler == dart2js || $compiler == dart2dart || $compiler == dartc ]
 http/test/*: Skip
+oauth2/test/*: Skip
 
 # Skip tests that use local file access if we're running in any browser
 [ $runtime == opera || $runtime == ff || $runtime == ie9 || $runtime == dartium || $runtime == chrome || $runtime == safari || $runtime == drt ]
 http/test/*: Skip
+oauth2/test/*: Skip
 intl/test/date_time_format_file_even_test: Skip
 intl/test/date_time_format_file_odd_test: Skip
 intl/test/find_default_locale_standalone_test: Skip
 
 [ $runtime == opera && $compiler == dart2js ]
 intl/test/find_default_locale_browser_test: Fail
 intl/test/date_time_format_http_request_test: Skip # Timeout.
 
 # Skip browser-specific Intl tests on VM
 [ $runtime == vm ]
@@ skipping 18 matching lines @@
 
 [ $system == windows ]
 http/test/request_test: Pass, Timeout # Issue 6594
 
 [ $compiler == dart2js || $compiler == dartc ]
 unittest/test/instance_test: Skip
 
 [ $compiler == none && $runtime == drt ]
 dartdoc/test/dartdoc_test: Skip # See dartbug.com/4541.
 args/test/args_test: Skip # http://dartbug.com/6744