[3.12] gh-118513: Fix sibling comprehensions with a name bound in one and global in the other (GH-118526) (#118548)

gh-118513: Fix sibling comprehensions with a name bound in one and global in the other (GH-118526)
(cherry picked from commit c8deb1e4b495bf97ab00c710dfd63f227e1fb645)

Co-authored-by: Carl Meyer <carl@oddbird.net>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Co-authored-by: Kirill Podoprigora <kirill.bast9@mail.ru>