apf: Add counters for dropped / passed packets

ApfFilter maintains separate counters for each reason why a packet was
passed or dropped by the filter logic.

There's also a total which should match the individual counters,
*unless* the APF interpreter aborted execution early due to an illegal
instruction or an out-of-bounds access.

Test: both on APFv2 and APFv4-capable device:
	runtest -x tests/net/java/android/net/ip/IpClientTest.java
	runtest -x tests/net/java/android/net/apf/ApfTest.java
	manual tests connected to an AP
Bug: 73804303
Change-Id: I54b17fcbb95dfaea5db975d282314ce73d79d6ec
Merged-In: I54b17fcbb95dfaea5db975d282314ce73d79d6ec
(cherry picked from commit 3cc40ea6)