Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait not implemented compiler/rustc_trait_selection/src/traits/vtable.rs@`vtable_entries`: The impossible predicates check in `vtable_entries` used `instantiate_own` which only includes the method's own `where` clauses, without the parent trait's bounds. Replace it with `instantiate_and_check_impossible_predicates` which also checks the trait ref itself, so unsatisfied supertrait bounds are caught and the method is marked `Vacant` instead of ICEing. Closes rust-lang/rust#137190. Closes rust-lang/rust#135470.