kselftest/runner: Print new line in print of timeout log
If a timeout failure occurs, kselftest kills the test process and prints
the timeout log. If the test process has killed while printing a log
that ends with new line, the timeout log can be printed in middle of the
test process output so that it can be seems like a comment, as below:
# test_process_log not ok 3 selftests: timers: nsleep-lat # TIMEOUT
This commit avoids such problem by printing one more line before the
TIMEOUT failure log.