Fix web_socket_ping_test to not use any timeouts longer than 100 ms.

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.
 
 # The testing infrastructure is using the dart:io Path and LineTransformer
@@ skipping 134 matching lines @@
 [ $compiler == dart2dart ]
 # Skip until we stabilize language tests.
 *: Skip
 
 [ $arch == arm ]
 io/internet_address_test: Fail  # localhost is an Unknown name?
 
 [ $arch == simarm ]
 out_of_memory_test: Skip # passes on Mac, crashes on Linux
 oom_error_stacktrace_test: Skip # Fails on Linux
-io/web_socket_ping_test: Skip # TODO(ajohnsen): Timeout issue
 io/test_runner_test: Pass, Fail # Issue 12413
 io/http_response_deadline_test: Pass, Fail # Issue 12850
 
 [ $arch == simmips || $arch == mips ]
 io/file_fuzz_test: Pass, Timeout
 io/web_socket_test: Pass, Slow
 io/http_server_response_test: Pass, Slow
 out_of_memory_test: Skip # passes on Mac, crashes on Linux
 oom_error_stacktrace_test: Skip # Fails on Linux
-io/web_socket_ping_test: Skip # TODO(ajohnsen): Timeout issue
 
 [ $arch == mips ]
 io/test_extension_test: Fail
 io/test_extension_fail_test: Fail
 io/dart_std_io_pipe_test: Fail
 io/file_read_special_device_test: Fail