Subpart8 for async drop (major2) - dropline in scopes for potentially async drops

[azhogin]

This is subpart 8 PR of #123948, just for review purposes.

Scopes processing for generate async drop preparations.
In scopes processing we need to consider potentially async drops as a hidden Yield and prepare dropline in the similar way as for Yield terminator.

Review only last commit, based on previous PR #129742

[rustbot]

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

This PR changes Stable MIR

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

This PR changes MIR

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

[RalfJung]

@azhogin please read what I wrote in one of your other PRs. You're spamming tons of people here.

Can you please mark these PRs as "draft" (before creating them, i.e. in the PR creation dialog), so that the bot doesn't ping dozens of people for each of them? :)

[bors]

☔ The latest upstream changes (presumably #130165) made this pull request unmergeable. Please resolve the merge conflicts.

[davidtwco]

r? @nikomatsakis is going to look into this