Prereq3 for async drop - LangItem registration for async_drop_in_place()::{{closure0}}

[azhogin]

This is subpart 3 PR of #123948, just for review purposes.
We have async_drop_in_place lang item for async fn async_drop_in_place<T>(...).

#[lang = "async_drop_in_place"]
pub async unsafe fn async_drop_in_place<T: ?Sized>(_to_drop: *mut T) { ... }

But we also need to generate shim for its returning value - coroutine async_drop_in_place<T>::{{closure0}}.
So, we need to bind some lang item to it. This patch registers LangItem::AsyncDropInPlacePoll for coroutine, when its constructor function is LangItem::AsyncDropInPlace.

Review only last commit, based on previous PR #129736

[rustbot]

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

This PR changes Stable MIR

cc @oli-obk, @celinval, @ouz-a

This PR changes MIR

cc @oli-obk, @RalfJung, @JakobDegen, @davidtwco, @celinval, @vakaras

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[bors]

☔ The latest upstream changes (presumably #130724) made this pull request unmergeable. Please resolve the merge conflicts.

[davidtwco]

r? @nikomatsakis is going to look into this