Prereq6 for async drop - templated coroutine processing and layout

[azhogin]

This is subpart 6 PR of #123948, just for review purposes.

For async_drop_in_place<T>(dropee)::{{closure0}} we need to perform shim codegen already with dropee type substituted.
To generate async drop glue we are generating sync-like drop glue using drop elaboration and then applying StateTransform pass to convert it into coroutine poll function. This coroutine has completely different layout dependent of dropee T, so it cannot be represented by generic coroutine with later T substitution (after codegen).

AsyncDropInPlacePoll lang item coroutine is considered as templated and will be codegen'ed already with GenericArgs substituted.

Review only last commit, based on previous PR #129740

[rustbot]

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

This PR changes Stable MIR

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

Some changes occurred to the CTFE / Miri engine

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Some changes occurred to MIR optimizations

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This PR changes MIR

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

[RalfJung]

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 #130091) made this pull request unmergeable. Please resolve the merge conflicts.

[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