Merge branch 'selftests/bpf: fix test_progs' log_level logic'

Andrii Nakryiko says:

====================

Fix the ability to request verbose (log_level=1) or very verbose (log_level=2)
logs with test_progs's -vv or -vvv parameters. This ability regressed during
recent bpf_prog_load() API refactoring. Also add
bpf_program__set_extra_flags() API to allow setting extra testing flags
(BPF_F_TEST_RND_HI32), which was also dropped during recent changes.
====================

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