Overflow row is used for GROUP BY if all of the above is true:
- WITH TOTALS is requested
- max_rows_to_group_by > 0
- group_by_overflow_mode = any
- totals_mode != after_having_exclusive
And in case of overflow row and external GROUP BY, once the temporary
file dumps to disk it resets without_key data variant to nullptr, so any
subsequent dump to disk will cause SIGSEGV.
Fix this, by recreating without_key data variant after dumping to disk,
instead of reseting to nullptr.
And also add sanity check (LOGICAL_ERROR) to make error more
deterministic in case of such error.
Found with fuzzer [1].
[1]: https://clickhouse-test-reports.s3.yandex.net/23929/e7027e052998540ee660d186727e20f9555b729d/fuzzer_ubsan/report.html#fail1
