Rollup merge of #115885 - RalfJung:dont-ignore-ice, r=oli-obk

don't globally ignore rustc-ice files

Reverts a change that happened in https://github.com/rust-lang/rust/pull/114586 but is unrelated to that PR and wasn't discussed.

ICE files appearing is somewhat of a nuisance, but I'd rather clean them up than have them accumulate in my source folder. `@oli-obk` if you want to ignore them you can add them to your local `.git/info/exclude`.