Refactor file utils (#10970)

### What problem does this PR solve?

As title.

### Type of change

- [x] Refactoring

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

common/file_utils.py

@@ -31,3 +31,9 @@ def get_project_base_directory(*args):
     if args:
         return os.path.join(PROJECT_BASE, *args)
     return PROJECT_BASE
+
+def traversal_files(base):
+    for root, ds, fs in os.walk(base):
+        for f in fs:
+            fullname = os.path.join(root, f)
+            yield fullname