FTBFS: TestMachineLimitMax fails on several architectures

As reported in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=834459
TestMachineLimitMax fails at least on armel, armhf and i686:
https://buildd.debian.org/status/logs.php?pkg=gitlab-ci-multi-runner&ver=1.4.1%2Bdfsg-1