UnsafePinned: implement opsem effects of UnsafeUnpin

[RalfJung]

This implements the next step for #125735: actually making UnsafePinned have special opsem effects by suppressing the noalias even if the type is wrapped in an Unpin wrapper.

For backwards compatibility we also still keep the Unpin hack, i.e. a type must be both Unpin and UnsafeUnpin to get noalias.

[rustbot]

The Miri subtree was changed

cc @rust-lang/miri

[rustbot]

r? @davidtwco

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[rustbot]

This PR modifies tests/auxiliary/minicore.rs.

cc @jieyouxu

[RalfJung]

Uh, what is happening with the link checker here? I have no idea why this PR would add new links to NonZeroInner...

[RalfJung]

Uh, no idea what's going on, but it some sort of rustdoc weirdness... Cc @rust-lang/rustdoc

[RalfJung]

@davidtwco will you be fine to review this or should I go look for someone else?

Not sure who else knows their way around our LLVM attribute handling here... @nikic @workingjubilee maybe?

[RalfJung]

@rustbot reroll

[davidtwco]

@davidtwco will you be fine to review this or should I go look for someone else?

Not sure who else knows their way around our LLVM attribute handling here... @nikic @workingjubilee maybe?

Sorry for the delay in getting back to you, some of this is a bit out of cache for me, so probably best to reroll.

[RalfJung]

@rustbot reroll

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.