Default execution on Windows fails when using forward slashes as directory separator

[AngelicosPhosphoros]

Example:

>hyperfine .\target\debug\have_types.exe
Benchmark 1: .\target\debug\have_types.exe
  Time (mean ± σ):      29.0 ms ±  10.1 ms    [User: 22.4 ms, System: 4.7 ms]
  Range (min … max):    26.0 ms …  85.1 ms    33 runs
> hyperfine ./target/debug/have_types.exe
Benchmark 1: ./target/debug/have_types.exe
Error: Command terminated with non-zero exit code 1 in the first benchmark run. Use the '-i'/'--ignore-failure' option if you want to ignore this. Alternatively, use the '--show-output' option to debug what went wrong.
> hyperfine --shell=none ./target/debug/have_types.exe
Benchmark 1: ./target/debug/have_types.exe
  Time (mean ± σ):      27.1 ms ±   8.3 ms    [User: 23.0 ms, System: 2.1 ms]
  Range (min … max):    25.0 ms …  77.2 ms    38 runs

As you can see, second launch fails.

System information:

OS Name: Microsoft Windows 10 Pro
System Version: 10.0.19045 Build 19045
>hyperfine --version
hyperfine 1.19.0