test/trace: add functional test cases

Example commands to run UT and check the traces with babeltrace viewer.

- Delete the existing /root/dpdk-traces/ directory if needed.
> sudo rm -rf /root/dpdk-traces/

- Start the dpdk-test
> sudo ./build/app/test/dpdk-test  -c 0x3 - --trace=.*

- Run trace_autotest
> trace_autotest

- View the traces with babletrace viewer.
> sudo babeltrace /root/dpdk-traces/

Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
Acked-by: David Marchand <david.marchand@redhat.com>