[ROCm][CI] Keep native datasets cache off shared NFS (#49516)

Signed-off-by: Andreas Karatzas <Andreas.Karatzas@amd.com>

.buildkite/scripts/hardware_ci/run-amd-test.sh

@@ -405,11 +405,14 @@ initialize_native_environment() {
   VLLM_CACHE_ROOT="${native_root}/cache/vllm"
   XDG_CACHE_HOME="${native_root}/cache/xdg"
   : "${HF_HOME:=/home/buildkite-agent/huggingface}"
+  # datasets uses POSIX locks that are unsupported by the shared HF NFS cache.
+  # Keep processed datasets job-local while retaining the persistent Hub cache.
+  HF_DATASETS_CACHE="${native_root}/cache/huggingface/datasets"
   : "${HF_HUB_DOWNLOAD_TIMEOUT:=300}"
   : "${HF_HUB_ETAG_TIMEOUT:=60}"
   export TMPDIR VLLM_RPC_BASE_PATH
   export TORCHINDUCTOR_CACHE_DIR TRITON_CACHE_DIR VLLM_CACHE_ROOT XDG_CACHE_HOME
-  export HF_HOME HF_HUB_DOWNLOAD_TIMEOUT HF_HUB_ETAG_TIMEOUT
+  export HF_HOME HF_DATASETS_CACHE HF_HUB_DOWNLOAD_TIMEOUT HF_HUB_ETAG_TIMEOUT
   export PYTORCH_ROCM_ARCH=""
 
   mkdir -p "${TMPDIR}" \
@@ -417,7 +420,8 @@ initialize_native_environment() {
     "${TRITON_CACHE_DIR}" \
     "${VLLM_CACHE_ROOT}" \
     "${XDG_CACHE_HOME}" \
-    "${HF_HOME}" || return 1
+    "${HF_HOME}" \
+    "${HF_DATASETS_CACHE}" || return 1
 
   echo "Native compile caches: VLLM_CACHE_ROOT=${VLLM_CACHE_ROOT} TORCHINDUCTOR_CACHE_DIR=${TORCHINDUCTOR_CACHE_DIR}"