cabal-solver: fix parseCabalOutput on Windows
cabal-solver: fix parseCabalOutput on Windows

martin-kolinek/stack,anton-dessiatov/stack,AndreasPK/stack,AndrewRademacher/stack,Blaisorblade/stack,AndrewRademacher/stack,Fuuzetsu/stack,Heather/stack,martin-kolinek/stack,MichielDerhaeg/stack,Heather/stack,deech/stack,sjakobi/stack,juhp/stack,AndreasPK/stack,mrkkrp/stack,Fuuzetsu/stack,deech/stack,sjakobi/stack,anton-dessiatov/stack,juhp/stack,Blaisorblade/stack,MichielDerhaeg/stack,mrkkrp/stack