tests/ui/runtime/on-broken-pipe/with-rustc_main.rs: Not needed so remove
related: https://github.com/rust-lang/rust/issues/145899#issuecomment-3705550673
print error from EnzymeWrapper::get_or_init(sysroot) as a note
r? @ZuseZ4
e.g.
1. when libEnzyme not found
```shell
$ rustc +stage1 -Z autodiff=Enable -C lto=fat src/main.rs
error: autodiff backend not found in the sysroot: failed to find a `libEnzyme-21` folder in the sysroot candidates:
* /Volumes/WD_BLACK_SN850X_HS_1TB/rust-lang/rust/build/aarch64-apple-darwin/stage1/lib
|
= note: it will be distributed via rustup in the future
```
2. when could not load libEnzyme successfully
```shell
rustc +stage1 -Z autodiff=Enable -C lto=fat src/main.rs
error: failed to load our autodiff backend: DlOpen { source: "dlopen(/Volumes/WD_BLACK_SN850X_HS_1TB/rust-lang/rust/build/aarch64-apple-darwin/stage1/lib/rustlib/aarch64-apple-darwin/lib/libEnzyme-21.dylib, 0x0005): tried: \'/Volumes/WD_BLACK_SN850X_HS_1TB/rust-lang/rust/build/aarch64-apple-darwin/stage1/lib/rustlib/aarch64-apple-darwin/lib/libEnzyme-21.dylib\' (slice is not valid mach-o file), \'/System/Volumes/Preboot/Cryptexes/OS/Volumes/WD_BLACK_SN850X_HS_1TB/rust-lang/rust/build/aarch64-apple-darwin/stage1/lib/rustlib/aarch64-apple-darwin/lib/libEnzyme-21.dylib\' (no such file), \'/Volumes/WD_BLACK_SN850X_HS_1TB/rust-lang/rust/build/aarch64-apple-darwin/stage1/lib/rustlib/aarch64-apple-darwin/lib/libEnzyme-21.dylib\' (slice is not valid mach-o file)" }
```
Matthias Krüger
dadacb6589