Use HandlerUtils for thread-safe ApfFilter.dump()

Modified ApfFilter.dump() to execute within
HandlerUtils.runWithScissorsForDump(), ensuring all access is on the
handler thread.  This allows safe removal of the synchronized keyword
from ApfFilter, improving efficiency.

Test: TH, manual test
Change-Id: Iace193214b14afe68556ca0230bc72f0e667805c
1 file changed