test(qwen-tts): guard CUDA 13 build concurrency

Keep the CUDA 13 FlashAttention packaging check tied to its serialized source-build guard so the runner OOM fix cannot be removed unnoticed.\n\nAssisted-by: Codex:gpt-5 [Codex]

Author: localai-org-maint-bot

backend/python/qwen-tts/test.sh

@@ -7,6 +7,9 @@ for cuda_version in 12 13; do
     grep -qx "flash-attn" "$backend_dir/requirements-cublas${cuda_version}-after.txt"
 done
 
+grep -q 'BUILD_PROFILE.*cublas13' "$backend_dir/install.sh"
+grep -q 'MAX_JOBS.*1' "$backend_dir/install.sh"
+
 if [ -d $backend_dir/common ]; then
     source $backend_dir/common/libbackend.sh
 else