The MySQL 5.6.36 merge (commit 0af98182
in MariaDB Server 10.0.31, 10.1.24, 10.2.7) introduced a change from
Oracle:
Bug#25551311 BACKPORT BUG #23517560 REMOVE SPACE_ID RESTRICTION
FOR UNDO TABLESPACES

Some debug assertions in MariaDB 10.2 were still assuming that the
InnoDB undo tablespace IDs start from 1. With the above mentioned
change, the undo tablespace IDs must be contiguous and nonzero.