Flux: remove the trusted/opaque opt-outs added for nightly-2026-08-21 #716

#687 needed two Flux opt-outs for upstream code Flux can't handle yet:

• num::from_ascii_bytes_radix_impl is flux::trusted: it uses subslice patterns (unsupported place (*_1)[1:]).
• ptr::NonNull is flux::opaque: its field is now a pattern type (pattern_type!(*const T is !null)), which Flux can't lower.

The rest of Flux's coverage was unchanged (same 35 constraints solved as main). Remove these once Flux supports both constructs.