Add pragma for edge-case code path

Author: abravalheri

setuptools/build_meta.py

@@ -432,7 +432,7 @@ def _build(cmd: list[str]):
 
         try:
             return _build(['bdist_wheel', '--dist-info-dir', metadata_directory])
-        except SystemExit as ex:
+        except SystemExit as ex:  # pragma: nocover
             # pypa/setuptools#4683
             if "--dist-info-dir" not in str(ex):
                 raise