Only the first half of the test works only on POSIX, the second half
passes on Windows as well.
A later test "real path removes other extra slashes" looks very similar,
but it does not make sense to split it in the same way: When two slashes
are prepended in front of an absolute DOS-style path on Windows, the
meaning of the path is changed (//server/share style), so that the test
cannot pass on Windows.
Signed-off-by: Johannes Sixt <j6t@kdbg.org> Acked-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>