Add patch to fix autopkgtest on s390x

These two tests fail on s390x machines, looks like some 32-bit issues we already have. Probably worth skipping these on 32-bit/s390x arch.

Test logs on Ubuntu: https://autopkgtest.ubuntu.com/results/autopkgtest-impish/impish/s390x/p/phpmyadmin/20210516_212523_5cd19@/log.gz