Auto merge of rust-lang#118138 - Nilstrieb:one-previous-error, r=WaffleLapkin

Fixes error count display is different when there's only one error left

Supersedes rust-lang#114759

### What did I do?

I did the small change in `rustc_errors` by hand. Then I did the other changes in `/compiler` by hand, those were just find replace on `*.rs` in the workspace. The changes in run-make are find replace for `run-make` in the workspace.

All other changes are blessed using `x test TEST --bless`. I blessed the tests that were blessed in rust-lang#114759.

### how to review this nightmare

ping bors with an `r+`. You should check that my logic is sound and maybe quickly scroll through the diff, but fully verifying it seems fairly hard to impossible. I did my best to do this correctly.

Thank you `@adrianEffe` for bringing this up and your initial implementation.

cc `@flip1995,` you said you want to do a subtree sync asap
cc `@RalfJung` maybe you want to do a quick subtree sync afterwards as well for Miri

r? `@WaffleLapkin`

Author: bors

core/src/intrinsics/mir.rs

@@ -193,7 +193,7 @@
 //! 27 | |     )
 //!    | |_____- binding declared here but left uninitialized
 //!
-//! error: aborting due to previous error
+//! error: aborting due to 1 previous error
 //!
 //! For more information about this error, try `rustc --explain E0381`.
 //! ```