MDEV-22488 test failures: parts.partition_debug_innodb /
           parts.partition_debug_myisam

The reason for the failure was a wrong printf() that accessed not existing
things on the stack.
The reason the falure was hard to find was that the partition_debug_...
tests disables core dumps, so there was no trace that the server had
crashed in the logs.

Fixed by fixing the faulty push_warning_printf() and splitting the tests
into two parts, one that test failures (with core dumps enabled) and one
part that test crash recovery.

The review and test splitting was done by Monty