cli unittests: delete click's CliRunner() instance after each test. Should help with leaked pipe handles.
cli unittests: delete click's CliRunner() instance after each test. Should help with leaked pipe handles.

theQRL/QRL,jleni/QRL,randomshinichi/QRL,randomshinichi/QRL,cyyber/QRL,cyyber/QRL,theQRL/QRL,jleni/QRL