Remove leftover mentions of XLOG_HEAP2_FREEZE_PAGE records
f83d709760d merged the separate XLOG_HEAP2_FREEZE_PAGE records into a
new combined prune, freeze, and vacuum record with opcode
XLOG_HEAP2_PRUNE_VACUUM_SCAN. Remove the last few references to
XLOG_HEAP2_FREEZE_PAGE records which were accidentally left behind.
Reported-by: Tomas Vondra
Reviewed-by: Robert Haas
Discussion: https://postgr.es/m/CA%2BTgmoY1tYff-1CEn8kYt5FsOrynTbtr%3DUZw%3D7mTC1Hv1HpeBQ%40mail.gmail.com