The test library puts helpers into $PATH, so we can simply call them
without specifying their location.
The suffix $X is also not necessary because .exe files on Windows can be
started without specifying their extension, and on other platforms it's
empty anyway.
Signed-off-by: Rene Scharfe <l.s.r@web.de> Acked-by: Jeff Hostetler <git@jeffhostetler.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>