Buildbot coverage of Videx

MDEV-39390 highlights a lack of ASAN testing, but looking further the suite=videx, being a not-default suite isn't executed.

As its about to be ASAN fixed I guess that's a starting point. Suite is available since 12.3

ghcr.io/bytedance/videx-server:0.2.0-preview-test2 as a companion container works well. It has a service on port 5001 which is the default value for videx_server_ip (e.g. "127.0.0.1:5001" grimance, is it too late to change the name).

If this is a companion container in the same network namespace this is easy. If it needs to be on its own hostname that's ok too, we'll just need to adjust the mtr suite to take a env variable.