tests: net: socket: af_packet: Add more tests to verify binding

In case the receiving packet socket is not bound to any specific
interface, or is explicitly bound to "any" interface (at index 0),
it should collect packets from all interfaces. Add test cases which
verify that.

Also, if a packet socket is bound to a specific interface, it should not
receive packets from others. Add a test case to verify that as well.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>