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

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

Supersedes #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 #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`

tests/ui/rfcs/rfc-2632-const-trait-impl/const-drop.precise.stderr

@@ -6,5 +6,5 @@ LL |     pub struct ConstDropWithBound<T: ~const SomeTrait>(pub core::marker::Ph
    |
    = note: this item cannot have `~const` trait bounds
 
-error: aborting due to previous error
+error: aborting due to 1 previous error