Enabling "Weight Loading Multiple GPU Test - Large Models" (vllm-project#18020)

Author: Alexei-V-Ivanov-AMD

.buildkite/test-pipeline.yaml

@@ -703,6 +703,7 @@ steps:
     - bash weight_loading/run_model_weight_loading_test.sh -c weight_loading/models.txt
 
 - label: Weight Loading Multiple GPU Test - Large Models # optional
+  mirror_hardwares: [amdexperimental] 
   working_dir: "/vllm-workspace/tests"
   num_gpus: 2
   gpu: a100