Turn read cache off for periodic update.
Like 498a96a4 says:
Aria with row_format=fixed uses IO_CACHE of type READ_CACHE for
sequential read in update loop. When history row is inserted inside
this loop the cache misses it and fails with error.
This applicable to any additional row inserts on UPDATE. In this case
it was initiated by UPDATE FOR PORTION.
Related to MDEV-20441.
DROP DATABASE would internally execute DROP TABLE on every contained
table and finally remove the directory. In InnoDB, DROP TABLE is
sometimes executed in the background. The table would be renamed to
a name that starts with #sql. The existence of these files would
prevent DROP DATABASE from succeeding.
CREATE OR REPLACE DATABASE can internally execute DROP DATABASE if
the directory already exists. This could fail due to the InnoDB
background DROP TABLE, possibly due to some tables that were
leftovers from earlier tests.
* don't suppress output unnecessary
* only run system versioning tests with two innodb combinations
* show results of delete/update (add SELECTs as needed)
