Enable arm64 runtime smoke execution

tests/test_runtime_distribution_build.py

@@ -92,6 +92,7 @@ class RuntimeDistributionBuildTests(unittest.TestCase):
             "managed_ingress_image",
             "garage_image",
             "test_mail_image",
+            "binfmt_image",
         ):
             self.assertIn(f"inputs.{input_name}", workflow)
 
@@ -148,6 +149,11 @@ class RuntimeDistributionBuildTests(unittest.TestCase):
         self.assertIn("Resolve managed dependency platform images", workflow)
         self.assertIn("--postgres-metadata", workflow)
         self.assertIn("--redis-metadata", workflow)
+        self.assertIn("Register arm64 execution for runtime smoke", workflow)
+        self.assertIn(
+            'docker run --privileged --rm "$BINFMT_IMAGE" --install arm64',
+            workflow,
+        )
         self.assertIn("runtime-smoke-amd64.json", workflow)
         self.assertIn("runtime-smoke-arm64.json", workflow)