Merge branch 'sk/mingw-tests-workaround'

Make tests pass on msysgit by mostly disabling ones that are infeasible on that platform. * sk/mingw-tests-workaround: t800[12]: work around MSys limitation t9902: mingw-specific fix for gitfile link files t4210: skip command-line encoding tests on mingw MinGW: disable legacy encoding tests t0110/MinGW: skip tests that pass arbitrary bytes on the command line MinGW: Skip test redirecting to fd 4