Rollup merge of #146187 - clarfonthey:const-drop-in-place, r=oli-obk

Unstably constify `ptr::drop_in_place` and related methods

Tracking: rust-lang/rust#109342
Supercedes: rust-lang/rust#145725

Makes methods const:

* `core::ptr::drop_in_place`
* `core::mem::ManuallyDrop::drop`
* `core::mem::MaybeUninit::assume_init_drop`
* `<[core::mem::MaybeUninit<_>]>::assume_init_drop`
* `<*mut _>::drop_in_place`
* `core::ptr::NonNull::drop_in_place`