Merge branch 'bpf-kselftest-improvements'

Merge branch 'bpf-kselftest-improvements'

Daniel Borkmann says:

====================
First one unifies the often repeated rlimit handling and the
second one enables and adds run-time tests for BPF tail calls
which provides useful coverage in particular for JITs.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>