[1/N] Refactor nightly test structure (#5479)

### What this PR does / why we need it?
This patch is a series of refactoring actions, including clarifying the
directory structure of nightly tests, refactoring the config retrieval
logic, and optimizing the workflow, etc. This is the first step:
refactoring the directory structure of nightly to make it more readable
and logical.

- vLLM version: v0.13.0
- vLLM main:
5326c89803

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

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

@@ -9,11 +9,15 @@ RED="\033[0;31m"
 NC="\033[0m" # No Color
 
 # Configuration
-LOG_DIR="/root/.cache/tests/logs"
-OVERWRITE_LOGS=true
 export LD_LIBRARY_PATH=/usr/local/Ascend/ascend-toolkit/latest/python/site-packages:$LD_LIBRARY_PATH
+# Home path for aisbench
 export BENCHMARK_HOME=${WORKSPACE}/vllm-ascend/benchmark
+
+# Logging configurations
 export VLLM_LOGGING_LEVEL="INFO"
+# Reduce glog verbosity for mooncake
+export GLOG_minloglevel=1
+# Set transformers to offline mode to avoid downloading models during tests
 export TRANSFORMERS_OFFLINE="1"
 
 # Function to print section headers
@@ -131,7 +135,7 @@ kill_npu_processes() {
 run_tests_with_log() {
     set +e
     kill_npu_processes
-    pytest -sv --show-capture=no tests/e2e/nightly/multi_node/test_multi_node.py
+    pytest -sv --show-capture=no tests/e2e/nightly/multi_node/scripts/test_multi_node.py
     ret=$?
     set -e
     if [ "$LWS_WORKER_INDEX" -eq 0 ]; then