Co-authored-by: Ben Kimock <kimockb@gmail.com>

Using `F_KINFO` fcntl flag, the kf_structsize field
needs to be set beforehand for that effect.

Remove reachable coverage without counters to maintain invariant that
either there is no coverage at all or there is a live coverage counter
left that provides the function source hash.

The motivating example would be a following closure:

```rust
    let f = |x: bool| {
        debug_assert!(x);
    };
```

Which, with span changes from rust-lang#93967, with disabled debug assertions,
after the final CFG simplifications but before removal of dead blocks,
gives rise to MIR:

```rust
fn main::{closure#0}(_1: &[closure@a.rs:2:13: 2:22], _2: bool) -> () {
    debug x => _2;
    let mut _0: ();

    bb0: {
        Coverage::Expression(4294967295) = 1 - 2;
        return;
    }

    ...
}
```

Constify a few `(Partial)Ord` impls

Only a few `impl`s are constified for now, as rust-lang#92257 has not landed in the bootstrap compiler yet and quite a few impls would need that fix.

This unblocks rust-lang#92228, which unblocks marking iterator methods as `default_method_body_is_const`.

…imulacrum

Implement `fs::get_path` for FreeBSD.

Using `F_KINFO` fcntl flag, the kf_structsize field
needs to be set beforehand for that effect.

correct the output of a `capacity` method example

The output of this example in std::alloc is different from which shown in the comment. I have tested it on both Linux and Windows.

clarify how write_bytes can lead to UB due to invalid values

Fixes rust-lang/unsafe-code-guidelines#330

Cc `@5225225`

…li-obk

don't ICE on invalid dyn calls

Due to rust-lang#50781 this is actually reachable.
Fixes rust-lang/miri#2432

r? `@oli-obk`

Remove reachable coverage without counters

Remove reachable coverage without counters to maintain invariant that
either there is no coverage at all or there is a live coverage counter
left that provides the function source hash.

The motivating example would be a following closure:

```rust
    let f = |x: bool| {
        debug_assert!(x);
    };
```

Which, with span changes from rust-lang#93967, with disabled debug assertions,
after the final CFG simplifications but before removal of dead blocks,
gives rise to MIR:

```rust
fn main::{closure#0}(_1: &[closure@a.rs:2:13: 2:22], _2: bool) -> () {
    debug x => _2;
    let mut _0: ();

    bb0: {
        Coverage::Expression(4294967295) = 1 - 2;
        return;
    }

    ...
}
```

Which also makes the initial instrumentation quite suspect, although
this pull request doesn't attempt to address that aspect directly.

Fixes rust-lang#98833.

r? `@wesleywiser` `@richkadel`

…-conversions, r=michaelwoerister

Avoid `&str`/`Symbol` to `String` conversions

follow-up to rust-lang#99342 and rust-lang#98668