Fix some unresolved supertypes. This is necessary to be able to enable
IR fake override builder by default (KT-61514), because it traverses all
supertypes and asserts that they're classes, so that it can build fake
overrides for declarations from there. Without this change, for example
`IrFakeOverrideBuilder.buildFakeOverridesForClass` would crash.
This change is needed due to using FIR as frontend for tests. In this
case finally block doesn't has coercion to unit so it's result must
be dropped manually.