bpf: remove test map scaffolding and user proper types

proper types and function helpers are ready. Use them in verifier testsuite.
Remove temporary stubs

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc kernel/bpf/test_stub.c
Simple merge

diff --cc samples/bpf/test_verifier.c
Simple merge