accuracy test is failing since nightly-2024-04-27

See #616. Failures appear to be due to https://github.com/rust-lang/rust/pull/120845. Using the unstable attribute mentioned in that PR fixes it:
```diff
--- a/tests/accuracy/main.rs
+++ b/tests/accuracy/main.rs
@@ -6,6 +6,7 @@ macro_rules! pos {
     };
 }
 
+#[collapse_debuginfo(yes)]
 macro_rules! check {
     ($($pos:expr),*) => ({
         verify(&[$($pos,)* pos!()]);
```
