fix in select(oid_nil) on dense tail:
fix in select(oid_nil) on dense tail:

with a point-nil select on a dense BAT, we must not try to use oid_nil for positional
lookups --- bug was revealed after recent property propagation improvements in BATslice

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb