Remove unused t/t8005/iso8859-5.txt

This file is no longer used since 54bc13c (t8005: Nobody writes Russian in
shift_jis, 2009-06-18).

Signed-off-by: Nanako Shiraishi <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Nanako Shiraishi