app/test: fix bonding mode 5 Tx check

app/test: fix bonding mode 5 Tx check

Test failed on verification if number of bytes
transmitted on each slave is not less than 90%
and greater than 110% of mean value of bytes transmitted
thru one slave. This was verified on a real system
but is difficult to achieve using virtualpmd.
That's why for unit tests only, it is sufficient to verify that with
high load (2 seconds transmission) all slaves are transmitting
so the traffic is balanced.

Fixes: 0c8396e6d786 ("bond: unit tests for mode 5")

Signed-off-by: Michal Jastrzebski <michalx.k.jastrzebski@intel.com>