Fix const qualification when executed after promotion
The const qualification was so far performed before the promotion and
the implementation assumed that it will never encounter a promoted.
With `const_precise_live_drops` feature, checking for live drops is
delayed until after drop elaboration, which in turn runs after
promotion. so the assumption is no longer true. When evaluating
`NeedsNonConstDrop` it is now possible to encounter promoteds.
Use type base qualification for the promoted. It is a sound
approximation in general, and in the specific case of promoteds and
`NeedsNonConstDrop` it is precise.
Fixes#89938.
a656bc5b08