test/bpf: add immediate load
test/bpf: add immediate load

New test-case to cover (BPF_LD | BPF_IMM | EBPF_DW) instruction.

Signed-off-by: Konstantin Ananyev <cbd5212b59ab42a210d72992d23a3aa17cfd3eaf@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk