Don't use Perl pack('Q') in 039_end_of_wal.pl.

Don't use Perl pack('Q') in 039_end_of_wal.pl.

'Q' for 64 bit integers turns out not to work on 32 bit Perl, as
revealed by the build farm.  Use 'II' instead, and deal with endianness.

Back-patch to 12, like bae868ca.

Discussion: https://postgr.es/m/ZQ4r1vHcryBsSi_V%40paquier.xyz