Only starting with MariaDB 10.3.8 (MDEV-16365), InnoDB can actually
handle ALTER IGNORE TABLE correctly when introducing a NOT NULL
attribute to a column that contains a NULL value. Between
MariaDB Server 10.0 and 10.2, we would incorrectly return an error
for ALTER IGNORE TABLE when the column contains a NULL value.
While the test case crashes a MariaDB 10.2 debug build only,
let us apply the fix to the earliest applicable MariaDB series (10.0)
to avoid any data corruption on a table-rebuilding ALTER TABLE
using ALGORITHM=INPLACE.
innobase_create_key_defs(): Use altered_table->s->primary_key
when a new primary key is being created.
