Fix memory leakage introduced into print_aligned_text by 8.4 changes

Fix memory leakage introduced into print_aligned_text by 8.4 changes
(failure to free col_lineptrs[] array elements) and exacerbated in the
current devel cycle (failure to free "wrap").  This resulted in moderate
bloat of psql over long script runs.  Noted while testing bug #5302,
although what the reporter was complaining of was backend-side leakage.