tests : disable backend sampler hip multi output (#26878)

* test-backend-sampler: skip multi_output_sampling_chain on HIP

The new multi_output_sampling_chain test uses top_k, whose backend probs
path needs CUB (unavailable on HIP), so sampled_probs is null and the test
aborts. Add it to the existing HIP skip list alongside the other TOP_K tests.

* ci: keep gpu-rocm logs in a per-run dir keyed by GitHub run id

The self-hosted gpu-rocm runner can't upload logs to Azure blob (egress
firewalled), so a run's logs were wiped by the next run. Write each run's
logs to $OUT/run-<run_id>-<attempt>/ so an Actions run URL maps to its logs.

* test-backend-sampler: also skip multi_output_cpu on HIP

Like the other TOP_K-based subtests, multi_output_cpu's backend sampler
never initializes on HIP (no CUB TOP_K), so it aborts. Add it to the skip list.

---------

Co-authored-by: Jim Wu <ywu@xilinx.com>

ci/run.sh

@@ -49,6 +49,14 @@ mkdir -p "$2"
 OUT=$(realpath "$1")
 MNT=$(realpath "$2")
 
+# gpu-rocm self-hosted runner can't upload logs to blob; keep each run's logs in
+# their own dir keyed by the GitHub run id so an Actions run URL maps to its logs.
+if [ -n "${GG_BUILD_ROCM}" ] && [ -n "${GITHUB_RUN_ID}" ]; then
+    OUT="$OUT/run-${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT:-1}"
+    mkdir -p "$OUT"
+    echo "ci results dir: $OUT"
+fi
+
 rm -f $OUT/*.log
 rm -f $OUT/*.exit
 rm -f $OUT/*.md

tests/test-backend-sampler.cpp

@@ -2105,7 +2105,9 @@ static std::vector<const backend_test_case *> collect_tests_to_run(const std::st
 #ifdef GGML_USE_HIP
             // TODO: remove this when https://github.com/ggml-org/llama.cpp/pull/26592 is merged
             if (test.name == "penalties" || test.name == "set_sampler" ||
-                test.name == "mixed"     || test.name == "top_p") {
+                test.name == "mixed"     || test.name == "top_p"       ||
+                test.name == "multi_output_sampling_chain" ||
+                test.name == "multi_output_cpu") {
                 fprintf(stderr, "Skipping test '%s' on HIP backend (no backend TOP_K support)\n", test.name.c_str());
                 continue;
             }