Test case for cli flags cannot work on windows

[Dmitriy Simushev]

This test case just cannot ends with a positive result when -a option is used on windows.

• Windows have no which command by default, so it will not be found.
• On windows systems something without an extension cannot be an executable. That's why bin/which is not treated as an executable and will not be found.

As the result output of bin/which will contain contain zero (by default) or one (if a custom which command is installed, ex. one from cygwin) lines. It means that this check always fails.

May be we should use another target command for the check?