Mark more standalone/io tests as flaky.

tests/standalone/standalone.status

Index: tests/standalone/standalone.status
diff --git a/tests/standalone/standalone.status b/tests/standalone/standalone.status
index 72d8a57e8002b8f8654a64a2cd0e1a23890274b4..1625845670d701a78abeb5573e52fe5e8488d22c 100644
--- a/tests/standalone/standalone.status
+++ b/tests/standalone/standalone.status
@@ -437,12 +437,19 @@ io/process_detached_test: Pass, Slow
 io/named_pipe_script_test: RuntimeError
 
 [ $compiler == dartk || $compiler == dartkp ]
+io/http_client_connect_test: Skip # Flaky.
 io/http_content_length_test: Skip # Flaky.
 io/http_proxy_test: Skip # Flaky.
 io/http_response_deadline_test: Skip # Flaky.
 io/http_reuse_server_port_test: Skip # Flaky.
 io/http_server_close_response_after_error_test: Skip # Flaky.
+io/http_shutdown_test: Skip # Flaky.
 io/raw_datagram_socket_test: Skip # Flaky.
+io/raw_secure_server_closing_test: Skip # Flaky
+io/raw_secure_server_closing_test: Skip # Flaky.
+io/secure_server_closing_test: Skip # Flaky.
+io/web_socket_error_test: Skip # Flaky
+io/web_socket_ping_test: Skip # Flaky.
 io/web_socket_test: Skip # Flaky.
 
 regress_29350_test: MissingCompileTimeError