In DWARF, alignment of types is specified in bits, as is made clear by the
parameter name `AlignInBits`. However, `rustc` was incorrectly passing a byte
alignment. This commit fixes that.

This was noticed in upstream LLVM when I tried to check in a test consisting of
LLVM IR generated from `rustc` and it triggered assertions [1].

[1]: https://reviews.llvm.org/D126835

…-copy, r=dtolnay

Stabilize `const_intrinsic_copy`

FCP has been completed: rust-lang#80697 (comment)
Closes rust-lang#80697

Allow ptr_from_addr_cast to fail

This is needed for rust-lang/miri#2133: I would like to have an option in Miri to error when a int2ptr cast is executed.

…ster

Specify DWARF alignment in bits, not bytes.

In DWARF, alignment of types is specified in bits, as is made clear by the
parameter name `AlignInBits`. However, `rustc` was incorrectly passing a byte
alignment. This commit fixes that.

This was noticed in upstream LLVM when I tried to check in a test consisting of
LLVM IR generated from `rustc` and it triggered assertions [1].

[1]: https://reviews.llvm.org/D126835

…tor-1, r=cjgillot

Impl Traits lowering minor refactors

This are unrelated changes on my RPIT refactor that may be better to merge before opening the main PR.

r? `@cjgillot`

cc `@nikomatsakis`

remove `BorrowckMode`

dead code after rust-lang#95565