WT_SESSION::verify documents its URI as optional, but the implementation never handles NULL: the URI gets parsed straight into __wt_schema_worker, where the first prefix match dereferences it and the process segfaults. WT-18582 may add a config option to use along with NULL URI, so this ticket should handle NULL URI if it is not already done so in WT-18582, and make sure NULL URI verifies all the tables.