A call to GetShortPathName can fail as files are not guaranteed to
have short name. This adds support for such case.
Fixes: https://github.com/libuv/libuv/issues/1258
PR-URL: https://github.com/libuv/libuv/pull/1267
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>