Most of the commands run by these specs actually prompt for user input
but for some reason `Open3` outside of Windows ignores that and goes on
with no user input. Windows does not like this.
This commit refactors these specs so that:
* They don't prompt for user input when not necessary.
* They pass proper user input when necessary.
As long as no user input is needed, most specs pass, so it allows to
remove the `:readline` tag from most of them.
https://github.com/rubygems/rubygems/commit/3dfabcdae4