Auto merge of #104833 - Swatinem:async-identity-future, r=compiler-errors

Remove `identity_future` indirection

This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.

Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]`annotation.

Fixes rust-lang/rust#104826.

Author: bors