Add test cases to cover IPv4 multicast filter

This commit covers the following counters:
- DROPPED_IPV4_BROADCAST_ADDR
- DROPPED_IPV4_BROADCAST_NET
- DROPPED_IPV4_MULTICAST
- DROPPED_IPV4_L2_BROADCAST
- PASSED_DHCP
- PASSED_IPV4_UNICAST

Test: atest NetworkStackTests:com.android.networkstack.android.net.apf.ApfFilterTest
Change-Id: I5a78dd5ae42fd2e995042355096688d8d8074a70
1 file changed