workaround mysql test container failures by forcing -debian variant

[mshima]

MySQL switched from Debian distribution to Oracle by default a few days ago.
Test containers are failing with -oracle variant, force it to use -debian instead.
Related to docker-library/mysql#877.

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[atomfrede]

I think we talked on another pr/issue about it. Can check later but it should be okay.

[mshima]

MySQL switched from Debian distribution to Oracle by default a few days ago.
That's the reason for JHipster CI failures.
See docker-library/mysql#877.

Oracle images is working out of the box at M1 but it's failing at CI.
We are trying to understand the behavior change.