MariaDB: Disappearing test cases or did another part of MySQL just become closed source?

The MariaDB blog reports that
Oracle has stopped bundling new test cases with the MySQL source.
Evidently the revision history is also no longer public. "MySQL test
cases were always an important part of the MySQL source tree. They were
particularly useful for storage engine developers and for other people
extending MySQL, for example, at Facebook, Twitter, and Taobao. But also
for Linux distributions which add their patches to the base MySQL, and even
to users, who don’t modify the sources — they still want to confirm that a
particular bug was fixed or that their custom-built binary has no obvious
flaws."