test: Reorder daemon fork to test in parent

To keep consistent with check_buxton tests, have the function calls
that are being tested be run in the parent not the child.
test: Fix missing test coverage

Because _exit (2) does not seem to call the statistic gathering
cleanup code gcc embeds buxton coverage was not being gathered after
forking. Fix this by moving to exit (3) which does not break make
check thankfully.