We have crash recovery tests, but those mainly target InnoDB. Aria is only involved in 10.4 to the extent that the server with Aria system tables starts after the crash.
We'll run similar tests but with Aria tables instead of InnoDB. Data creation needs to be adjusted, pre-crash DML can remain basically the same, after-recovery checks might need to be adjusted, post-crash DML/DDL can remain the same.
The tests are to be run in Travis regularly (daily at first, weekly after GA) along with other various tests.
MDEV-16421 - Make system tables crash safe