split binary from text portion

Author: rickeylev

python/private/stage2_bootstrap_template.py

@@ -71,8 +71,9 @@ def get_build_data(self):
             path = os.path.normpath(path)
         try:
             # Use utf-8-sig to handle Windows BOM
-            with open(path, encoding="utf-8-sig") as fp:
-                return fp.read()
+            with open(path, 'rb') as fp:
+                data = fp.read()
+            return data.decode('utf-8-sig')
         except Exception as exc:
             if hasattr(exc, "add_note"):
                 exc.add_note(f"runfiles lookup path: {rlocation_path}")