Handle Redis under arm64 CI emulation

tools/checks/runtime-image-smoke.py

@@ -259,6 +259,11 @@ def run_smoke(
         "--mount",
         f"type=volume,source={names['volume']},target=/var/lib/govoplan",
     ]
+    redis_command = ["redis-server", "--save", "", "--appendonly", "no"]
+    if platform == "linux/arm64":
+        # QEMU user-mode execution triggers Redis's host-kernel COW guard even
+        # though this isolated smoke disables every persistence mechanism.
+        redis_command.extend(("--ignore-warnings", "ARM64-COW-BUG"))
 
     try:
         _run(("docker", "network", "create", names["network"]), timeout=timeout)
@@ -308,11 +313,7 @@ def run_smoke(
                 "--tmpfs",
                 "/data:rw,noexec,nosuid,size=64m",
                 redis_image,
-                "redis-server",
-                "--save",
-                "",
-                "--appendonly",
-                "no",
+                *redis_command,
             ),
             timeout=timeout,
         )