Rollup merge of #109423 - fmease:iat-selection-erase-regions-in-self-ty, r=compiler-errors

Use region-erased self type during IAT selection

Split off from #109410 as discussed.
Fixes #109299.

Re UI test: I use a reproducer of #109299 that contains a name resolution error instead of reproducer [`regionck-2.rs`](https://github.com/rust-lang/rust/blob/fc7ed4af165c27ab5914b93251194f826920cc65/tests/ui/associated-inherent-types/regionck-2.rs) (as found in the `AliasKind::Inherent` PR) since it would (incorrectly) pass typeck in this PR due to the lack of regionck and I'd rather not make *that* a regression test (with or without `known-bug`).

``@rustbot`` label F-inherent_associated_types

r? ``@compiler-errors``

Author: matthiaskrgr