[C++] Harden synthetic OOM tests for mimalloc#49281

k8ika0s wants to merge 1 commit intoapache:mainapache/arrow:mainfrom

k8ika0s:codex/s390x-pr01-oom-testsk8ika0s/arrow_s390x:codex/s390x-pr01-oom-testsCopy head branch name to clipboard