app/test: unit tests for bonding mode 4

app/test: unit tests for bonding mode 4

This patch adds unit tests for mode 4. It is split into separate
file to avoid problems with other modes that does not need to
look into packets payload.
This patch includes also a modification of maximum number of ports
used in their tests for bonding modes 0-3 from 16 to 6.

Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Signed-off-by: Tomasz Kulasek <tomaszx.kulasek@intel.com>
Acked-by: Declan Doherty <declan.doherty@intel.com>