svlog: typeck: Add empty cast query for new types
svlog: typeck: Add empty cast query for new types

Duplicate the `cast_expr_type_inner` function to derive a version that
operates on the new types. This will be gradually uncommented and
modified to leverage the new type system, and will eventually replace
the old query.

fabianschuiki/moore,fabianschuiki/moore,fabianschuiki/moore,fabianschuiki/moore,fabianschuiki/moore