[Nightly] Optimize nightly CI (#4509)

### What this PR does / why we need it?
1. Optimize multi-node waiting logic
2. Remove the `tee` pipeline for logs, which will lead to hang issue

### How was this patch tested?


- vLLM version: v0.12.0
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.12.0

Signed-off-by: wangli <wangli858794774@gmail.com>

tests/e2e/nightly/multi_node/scripts/lws.yaml.jinja2

@@ -87,7 +87,7 @@ spec:
               - name: VLLM_ASCEND_REMOTE_URL
                 value: {{ vllm_ascend_remote_url | default("https://github.com/vllm-project/vllm-ascend.git") }}
               - name: RESULT_FILE_PATH
-                value: {{ result_file_path | default("/root/.cache/tests/ret/test_result.txt") }}
+                value: {{ result_file_path | default("/root/.cache/tests/ret") }}
               - name: FAIL_TAG
                 value: {{ fail_tag | default("FAIL_TAG") }}
             command:

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

@@ -127,19 +127,14 @@ kill_npu_processes() {
 run_tests_with_log() {
     set +e
     kill_npu_processes
-    BASENAME=$(basename "$CONFIG_YAML_PATH" .yaml)
-    # each worker should have log file
-    LOG_FILE="${RESULT_FILE_PATH}/${BASENAME}_worker_${LWS_WORKER_INDEX}.log"
-    mkdir -p ${RESULT_FILE_PATH}
-    pytest -sv tests/e2e/nightly/multi_node/test_multi_node.py 2>&1 | tee $LOG_FILE
-    ret=${PIPESTATUS[0]}
+    pytest -sv tests/e2e/nightly/multi_node/test_multi_node.py
+    ret=$?
     set -e
     if [ "$LWS_WORKER_INDEX" -eq 0 ]; then
         if [ $ret -eq 0 ]; then
             print_success "All tests passed!"
         else
             print_failure "Some tests failed!"
-            mv LOG_FILE error_${LOG_FILE}
         fi
     fi
 }