tests/fate.sh: If cat *.rep fails try it with a for loop.

Fixes fate on haiku, where cat dies due to too many arguments
xargs could be used too but we do not use xargs currently so it
would be an additional dependency.

Also the plain cat is left in place as it is faster than the loop

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
