`tests/ui/unpretty/staged-api-invalid-path-108697.rs` may fail on non English Windows installs

Ran this command on Windows 11:

./x.py t --target x86_64-pc-windows-gnullvm --host x86_64-pc-windows-gnullvm tests/ui/unpretty/staged-api-invalid-path-108697.rs

This exact invocation requires prebuilt host gnullvm toolchain, but I suppose other Windows targets are also affected, although I cannot test them.

Expected test to pass, instead it failed with:

running 1 tests

[ui] tests\ui\unpretty\staged-api-invalid-path-108697.rs ... F


failures:

---- [ui] tests\ui\unpretty\staged-api-invalid-path-108697.rs stdout ----
$DIR\lol
$DIR\staged-api-invalid-path-108697.rs
diff of stderr:

-       error: couldn't read $DIR/lol: No such file or directory (os error 2)
+       error: couldn't read $DIR/lol: Nie można odnaleźć określonego pliku. (os error 2)
2         --> $DIR/staged-api-invalid-path-108697.rs:8:1
3          |
4       LL | mod foo;


The actual stderr differed from the expected stderr.
Actual stderr saved to H:\projects\rust\build\x86_64-pc-windows-gnullvm\test\ui\unpretty\staged-api-invalid-path-108697\staged-api-invalid-path-108697.stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args unpretty\staged-api-invalid-path-108697.rs`

error: 1 errors occurred comparing output.
status: exit code: 1
command: PATH="H:\projects\rust\build\x86_64-pc-windows-gnullvm\stage1\bin;H:\projects\rust\build\x86_64-pc-windows-gnullvm\stage0-bootstrap-tools\x86_64-pc-windows-gnullvm\release\deps;H:\rust\bin;C:\Users\mateusz\bin;C:\Program Files\Git\mingw64\bin;C:\Program Files\Git\usr\local\bin;C:\Program Files\Git\usr\bin;C:\Program Files\Git\usr\bin;C:\Program Files\Git\mingw64\bin;C:\Program Files\Git\usr\bin;C:\Users\mateusz\bin;C:\Program Files\Alacritty;C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v12.1\bin;C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v12.1\libnvvp;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Windows\System32\OpenSSH;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files\dotnet;C:\Program Files\NVIDIA Corporation\Nsight Compute 2023.1.1;C:\Program Files\WezTerm;C:\Program Files\NVIDIA Corporation\NVIDIA App\NvDLISR;C:\Program Files\Git\cmd;C:\Program Files\Process Lasso;C:\Users\mateusz\.cargo\bin;C:\Users\mateusz\AppData\Local\Microsoft\WindowsApps;C:\Users\mateusz\AppData\Local\JetBrains\Toolbox\scripts;C:\Users\mateusz\AppData\Local\GitHubDesktop\bin;C:\Users\mateusz\AppData\Local\Programs\Microsoft VS Code\bin;H:\msys64\clang64\bin;C:\Users\mateusz\AppData\Local\Microsoft\WinGet\Links;C:\Program Files\Git\usr\bin\vendor_perl;C:\Program Files\Git\usr\bin\core_perl" "H:\\projects\\rust\\build\\x86_64-pc-windows-gnullvm\\stage1\\bin\\rustc.exe" "H:\\projects\\rust\\tests\\ui\\unpretty\\staged-api-invalid-path-108697.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=C:\\Users\\mateusz\\.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=H:\\projects\\rust\\vendor" "--sysroot" "H:\\projects\\rust\\build\\x86_64-pc-windows-gnullvm\\stage1" "--target=x86_64-pc-windows-gnullvm" "--check-cfg" "cfg(FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "H:\\projects\\rust\\build\\x86_64-pc-windows-gnullvm\\test\\ui\\unpretty\\staged-api-invalid-path-108697" "-A" "unused" "-A" "internal_features" "-Crpath" "-Cdebuginfo=0" "-Lnative=H:\\projects\\rust\\build\\x86_64-pc-windows-gnullvm\\native\\rust-test-helpers" "-L" "H:\\projects\\rust\\build\\x86_64-pc-windows-gnullvm\\test\\ui\\unpretty\\staged-api-invalid-path-108697\\auxiliary" "-Zunpretty=mir"
stdout: none
--- stderr -------------------------------
error: couldn't read H:\projects\rust\tests\ui\unpretty\lol: Nie można odnaleźć określonego pliku. (os error 2)
  --> H:\projects\rust\tests\ui\unpretty\staged-api-invalid-path-108697.rs:8:1
   |
LL | mod foo;
   | ^^^^^^^^

error: aborting due to 1 previous error
------------------------------------------



failures:
    [ui] tests\ui\unpretty\staged-api-invalid-path-108697.rs

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 17699 filtered out; finished in 36.93ms

Some tests failed in compiletest suite=ui mode=ui host=x86_64-pc-windows-gnullvm target=x86_64-pc-windows-gnullvm
Build completed unsuccessfully in 0:00:08

The error Nie można odnaleźć określonego pliku. resembles expected English The system cannot find the file specified. (the test would normalize that to No such file or directory), but it's displayed with the OS language (Polish).

Start with tests/ui/unpretty/staged-api-invalid-path-108697.rs and its expected stderr, then reproduce the reported x.py UI test on a non-English Windows installation. Trace how the UI test normalizes the localized missing-file error; done means this test passes without requiring English Windows while retaining the expected diagnostic structure.