[bugfix]Intermittent CI failure in the triton runtime jit (#5733)

### What this PR does / why we need it?
fix bug : https://github.com/vllm-project/vllm-ascend/issues/5634
Intermittent CI failure due to a compilation error in the triton
operator
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef

---------

Signed-off-by: Meihan-chen <jcccx.cmh@gmail.com>

tests/e2e/nightly/multi_node/scripts/run.sh

@@ -127,6 +127,10 @@ install_extra_components() {
 
 install_triton_ascend() {
     echo "====> Installing triton_ascend"
+    apt-get install -y clang-15
+    update-alternatives --install /usr/bin/clang clang /usr/bin/clang-15 20
+    update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-15 20
+    clang -v
 
     BISHENG_NAME="Ascend-BiSheng-toolkit_aarch64_20260105.run"
     BISHENG_URL="https://vllm-ascend.obs.cn-north-4.myhuaweicloud.com/vllm-ascend/${BISHENG_NAME}"