selftests/bpf: add tests for arena vma split and fork#12400

kernel-patches-daemon-bpf[bot] wants to merge 2 commits into

bpf-next_basekernel-patches/bpf:bpf-next_basefrom

series/1108395=>bpf-nextkernel-patches/bpf:series/1108395=>bpf-nextCopy head branch name to clipboard