[nvbugs/6215678][fix] Write aiperf artifacts to per-run subdir for stress test

aiperf was given a single shared --output-artifact-dir, so each concurrency
run overwrote the previous export and no <model>-openai-completions-<...>
subdir existed for extract_stress_test_metrics to parse, raising
"No model directories found ...". Point --output-artifact-dir at a unique
per-run subdir so every run is preserved and the directory-name parser
matches. Gitignore the test-generated artifacts dir and remove the obsolete
waivers.

Signed-off-by: tensorrt-cicd <90828364+tensorrt-cicd@users.noreply.github.com>

Author: tensorrt-cicd

.gitignore

@@ -111,6 +111,9 @@ enroot/tensorrt_llm.devel.sqsh
 # MacOSX Files
 .DS_Store
 
+# stress test aiperf output artifacts
+tests/integration/defs/stress_test/artifacts/
+
 # Agent related files
 .claude/agent-memory/
 .claude/agent-tests/perf-test-sync/report.html

tests/integration/defs/stress_test/stress_test.py

@@ -964,7 +964,9 @@ def create_aiperf_command(model_name,
         "--concurrency",
         str(concurrency),
         "--output-artifact-dir",
-        ARTIFACTS_DIR,
+        os.path.join(
+            ARTIFACTS_DIR,
+            f"{model_name}-openai-completions-concurrency{concurrency}"),
         # "--verbose",
     ]