tests(binary): has become flaky on Windows

It sometimes fails with:

```text
[Suite] fmt, with --update, without --yes, for an exercise that is not formatted (no diff, and exits with 1)
    D:\a\configlet\configlet\tests\test_binary.nim(1221, 21): Check failed: exitCode == 1
    exitCode was -1073741819
  [FAILED] -e bob
```