Rollup merge of #56017 - alexcrichton:debug-test, r=alexcrichton

std: Add debugging for a failing test on appveyor I'm not sure why this is failing, so let's hopefully get some more information to help investigation!

Author: kennytm

src/libstd/time.rs

@@ -481,7 +481,8 @@ mod tests {
  let (a, b) = ($a, $b);
  if a != b {
  let (a, b) = if a > b {(a, b)} else {(b, a)};
- assert!(a - Duration::new(0, 100) <= b);
+ assert!(a - Duration::new(0, 100) <= b,
+ "{:?} is not almost equal to {:?}", a, b);
  }
  })
  }