net: Add tests for bonding and team address list management

Test that the bonding and team drivers clean up an underlying device's
address lists (dev->uc, dev->mc) when the aggregated device is deleted.

Test addition and removal of the LACPDU multicast address on underlying
devices by the bonding driver.

v2:
* add lag_lib.sh to TEST_FILES

v3:
* extend bond_listen_lacpdu_multicast test to init_state up and down cases
* remove some superfluous shell syntax and 'set dev ... up' commands

Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>