Fix standalone/io/test_extension_test on SIMDBC64.

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.
 
 packages_file_test: Skip # Issue 26715
@@ skipping 300 matching lines @@
 package/scenarios/invalid/same_package_twice_test: Skip
 package/scenarios/invalid/non_existent_packages_file_test: Skip
 package/scenarios/empty_packages_file/empty_packages_file_noimports_test: Skip
 package/scenarios/packages_option_only/packages_option_only_noimports_test: Skip
 package/scenarios/packages_option_only/packages_option_only_test: Skip
 
 [ $arch == simdbc || $arch == simdbc64 ]
 # TODO(vegorov) SIMDBC interpreter doesn't support coverage yet.
 full_coverage_test: Skip
 
-[ $arch == simdbc64 ]
-io/test_extension_test: Fail # Issue #27480
-
 # SIMDBC interpreter doesn't support lazy linking of natives.
 link_natives_lazily_test: SkipByDesign
 
 # SIMDBC interpreter doesn't support --no_lazy_dispatchers
 no_lazy_dispatchers_test: SkipByDesign
 
 [ $compiler == precompiler && $runtime == dart_precompiled && $system == android ]
 io/*: Skip # Issue #26376
 
 typed_data_isolate_test: Skip # Issue #26376
@@ skipping 11 matching lines @@
 package/*: SkipByDesign # Launches VMs in interesting ways.
 
 [ $builder_tag == no_ipv6 ]
 io/http_bind_test: Skip
 io/raw_datagram_socket_test: Skip
 io/socket_source_address_test: Skip
 io/socket_bind_test: Skip
 io/http_proxy_advanced_test: Skip
 io/http_ipv6_test: Skip
 io/socket_ipv6_test: Skip