bltin_exc: Removed the leaf_exc flag in the structure, which was only used to build the fallback string-based exception.
bltin_exc: Removed the leaf_exc flag in the structure, which was only
used to build the fallback string-based exception.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator