pg_upgrade: further tweaking of make_outputdirs().
Use the same error message for all cases of pathname overrun,
since users aren't going to much care which one was too long.
Add missing newline to said error (as pg_upgrade's version
of pg_fatal requires that).
Add pathname overrun checks for the individual log files,
not just the directories.
Remove initial newline in log files; the new scheme here
guarantees that we'll never be appending to an old file.
Kyotaro Horiguchi and Tom Lane
Discussion: https://postgr.es/m/
20220613.120551.
729848632120189555.horikyota.ntt@gmail.com