When view_update_builder::on_results() hits the path where the update
fragment reader is already exhausted, it still needs to keep tracking
existing range tombstones and apply them to encountered rows.
Otherwise a row covered by an existing range tombstone can appear
alive while generating the view update and create a spurious view row.
Update the existing tombstone state even on the exhausted-reader path
and apply the effective tombstone to clustering rows before generating
the row tombstone update. Add a cqlpy regression test covering the
partition-delete-after-range-tombstone case.
Fixes: SCYLLADB-1649
Closesscylladb/scylladb#29481
(cherry picked from commit 073710a661)
Closesscylladb/scylladb#29649
f318968cfe