Added a bpf selftest in test_progs at tools directory for stacktrace.
The test will populate a hashtable map and a stacktrace map
at the same time with the same key, stackid.
The user space will compare both maps, using BPF_MAP_LOOKUP_ELEM
command and BPF_MAP_GET_NEXT_KEY command, to ensure that both have
the same set of keys.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>