[ci][gh200] dockerfile clean up (#11351)

Signed-off-by: drikster80 <ed.sealing@gmail.com>
Signed-off-by: youkaichao <youkaichao@gmail.com>
Co-authored-by: drikster80 <ed.sealing@gmail.com>
Co-authored-by: cenzhiyao <2523403608@qq.com>

.buildkite/run-gh200-test.sh

@@ -4,6 +4,9 @@
 # It serves a sanity check for compilation and basic model usage.
 set -ex
 
+# Skip the new torch installation during build since we are using the specified version for arm64 in the Dockerfile
+python3 use_existing_torch.py
+
 # Try building the docker image
 DOCKER_BUILDKIT=1 docker build . \
   --target vllm-openai \