Disable 031_recovery_conflict.pl until after minor releases.

Disable 031_recovery_conflict.pl until after minor releases.

f40d362a667 disabled part of 031_recovery_conflict.pl due to instability
that's not trivial to fix in the back branches. That fixed most of the
issues. But there was one more failure (on lapwing / REL_10_STABLE).

That failure looks like it might be caused by a genuine problem. Disable the
test until after the set of releases, to avoid packagers etc potentially
having to fight with a test failure they can't do anything about.

Discussion: https://postgr.es/m/3447060.1652032749@sss.pgh.pa.us
Backpatch: 10-14