selftests/bpf: Verifier/xdp_direct_packet_access.c converted to inline assembly

Test verifier/xdp_direct_packet_access.c automatically converted to use inline assembly.
Original test would be removed in the next patch.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230328020813.392560-2-eddyz87@gmail.com