get_next_line, test 40 fails when multiple fd is not supported with BUFF_SIZE = 3 or 6 or7

[nmanzini]

Problem

if the user's get_next_line.c does not support multiple file descriptors test (like mine used to do) 30_bonus_multiple_fd.spec.c leaves chars in the buffer, but only if the BUFF SIZE is 3 6 or 7. This can make 40_hard_test_medium_string.spec.c fail.

reasons

the first test of 30 is passed also with no multiple FD supported ("aaa\nbbb\n"), but the second one fails ("111\n222\n") and some combination of 222 is left in the static variable for next time.

going to test 40_hard_test_medium_string.spec.c some of those 222 stays in the static variable and can result into false negative. in my case at the beginning of every call of the function I would check if there were still chars in the static variable and pass them to *line.
My Lorem Ipsum... would always have some combination of 222 at the beginning if BUFF SIZE is 3 or 6 or 7.

bouns image