gh-98852: Fix subscription of type aliases (GH-98920)

Fix subscription of type aliases containing bare generic types or types
like TypeVar: for example tuple[A, T][int] and tuple[TypeVar, T][int],
where A is a generic type, and T is a type variable.
(cherry picked from commit 0e15c31c7e9907fdbe38a3f419b669fed5bb3b33)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>