[Test] Unify L2/L3 test layout, Buildkite steps, and test helpers (#2556)

Signed-off-by: wangyu <410167048@qq.com>
Signed-off-by: Huang, Zeyu <11222265+fhfuih@users.noreply.github.com>
Signed-off-by: wangyu <53896905+yenuo26@users.noreply.github.com>
Co-authored-by: Huang, Zeyu <11222265+fhfuih@users.noreply.github.com>

docs/contributing/ci/test_guide.md

@@ -80,7 +80,7 @@ Our test scripts use the pytest framework. First, please use `git clone https://
 
     ```bash
     cd tests
-    pytest -s -v -m "full_model and omni and H100" --run-level=full_model
+    pytest -s -v -m "full_model and (omni or tts) and H100" --run-level=full_model
     ```
 
 === "L5 level"