`dotnet reference remove` doesn't work correctly when a relative path to a directory is passed

Version: 10.0.300

Repro steps:
```ps1
dotnet new classlib -o lib
dotnet new console -o app
cd app
dotnet reference add ..\lib
dotnet reference remove ..\lib
```

Got: ```Project reference `..\..\lib\lib.csproj` could not be found.``` (Notice the `..\..` which is wrong, it should be just one level `..`)