Revert "Rollup merge of #122661 - estebank:assert-macro-span, r=petrochenkov"

This reverts commit 1eeb8e8b151d1da7daa73837a25dc5f7a1a7fa28, reversing
changes made to 324bf2b9fd8bf9661e7045c8a93f5ff0ec1a8ca5.

Unfortunately the assert desugaring change is not backwards compatible,
see RUST-145770.

Code such as

```rust
#[derive(Debug)]
struct F {
    data: bool
}

impl std::ops::Not for F {
  type Output = bool;
  fn not(self) -> Self::Output { !self.data }
}

fn main() {
  let f = F { data: true };

  assert!(f);
}
```

would be broken by the assert desugaring change. We may need to land
the change over an edition boundary, or limit the editions that the
desugaring change impacts.

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/ui/consts/control-flow/assert.stderr b/tests/ui/consts/control-flow/assert.stderr
index deaad6abbcc..026097a6ba0 100644
--- a/tests/ui/consts/control-flow/assert.stderr
+++ b/tests/ui/consts/control-flow/assert.stderr
@@ -1,8 +1,8 @@
 error[E0080]: evaluation panicked: assertion failed: false
-  --> $DIR/assert.rs:5:23
+  --> $DIR/assert.rs:5:15
    |
 LL | const _: () = assert!(false);
-   |                       ^^^^^ evaluation of `_` failed here
+   |               ^^^^^^^^^^^^^^ evaluation of `_` failed here
 
 error: aborting due to 1 previous error