Hi.
lazy_scan_heap: avoid vacuum block, already vacuumed.
Previously, in lazy_scan_heap() *next_fsm_block_to_vacuum*
is set with blkno, but FreeSpaceMapVacuumRange uses an exclusive end,
so passing blkno + 1 covers blkno itself.
Advance *next_fsm_block_to_vacuum* to blkno + 1, so the next call begins
at the first unvacuumed block and does not re-vacuum blkno.
best regards,
Ranier Vilela