Note: this change is required on the 6.0 branch and earlier

Our older branches are still using ubuntu1804-zeries-large and Ubuntu 18.04 is end of life. We should migrate to newer distros where ubuntu1804-zeries-large is in use.

The tests running on this distro check data written to disk on a large endian machine can be read on a little endian machine and vice versa, so we need to make sure endianess of the new distro is identical.

As part of this ticket we should also check if there are other Ubuntu 18.04 distros being used. If it's easy we can make the change in this ticket, and otherwise spin up a follow on ticket