SCIFRBool - Update SectionOp generation pass

The lack of a terminator on `section`, plus this code, makes the implicit assumption that only the results of the very last op in a `section` are the output of the entire `section` op. If you want to be able to have a section produce multiple results, you would probably need a terminator at that point.

If these are the intended semantics of `section`, this should be added to the tablegen description for the `section` op.

_Originally posted by @j2kun in https://github.com/google/heir/pull/2594#discussion_r2885616203_