s390x: Fix PyArrow build and add CPU test script for Buildkite CI

Signed-off-by: Nishan Acharya <[email protected]>

Author: Nash-123

Diff for: .buildkite/run-cpu-test-s390x.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+# This script build the CPU docker image and run the offline inference inside the container.
+# It serves a sanity check for compilation and basic model usage.
+set -ex
+
+# Setup cleanup
+remove_docker_container() { docker rm -f cpu-test || true; docker system prune -f; }
+trap remove_docker_container EXIT
+remove_docker_container
+
+# Try building the docker image
+docker build -t cpu-test -f docker/Dockerfile.s390x .

Diff for: docker/Dockerfile.s390x

@@ -58,7 +58,7 @@ RUN --mount=type=cache,target=/root/.cache/uv \
     cd ../../python && \
     export PYARROW_PARALLEL=4 && \
     export ARROW_BUILD_TYPE=release && \
-    uv pip install -r requirements/build.txt && \
+    uv pip install -r requirements-build.txt && \
     python setup.py build_ext --build-type=$ARROW_BUILD_TYPE --bundle-arrow-cpp bdist_wheel
 
 FROM python-install AS numa-build
@@ -149,4 +149,5 @@ USER 2000
 WORKDIR /home/vllm
 
 # Set the default entrypoint
-ENTRYPOINT ["python", "-m", "vllm.entrypoints.openai.api_server"]
+ENTRYPOINT ["python", "-m", "vllm.entrypoints.openai.api_server"]
+