[Gardening] Mark http_(basic|launch)_test as flaky.

tests/standalone/standalone.status

Index: tests/standalone/standalone.status
diff --git a/tests/standalone/standalone.status b/tests/standalone/standalone.status
index daef69f988ce0667d474a992d30688a1f63d022a..ab8c2523e4914b22979e32f9013733b0125676c5 100644
--- a/tests/standalone/standalone.status
+++ b/tests/standalone/standalone.status
@@ -63,8 +63,10 @@ io/raw_server_socket_cancel_test: Skip # Issue 28182
 io/http_proxy_test: Skip
 io/secure_builtin_roots_test: Skip
 
-# This test might be slow on an opt counter threshold bot.
-io/http_basic_test: Pass, Slow
+# These tests might be slow on an opt counter threshold bot.
+# They also time out on the bot occasionally => flaky test issue 28046
+io/http_basic_test: Pass, Slow, Timeout  # Issue 28046
+io/http_launch_test: Pass, Slow, Timeout  # Issue 28046
 
 
 [ $compiler == none && ($runtime == drt || $runtime == dartium) ]