Skip useless calls to now() in PacketHandler.java

[jogger]

From void run()

long queueTime = packet.getLifetime();
long handleStart = _context.clock().now();
long handleTime = _context.clock().now() - handleStart;

[jogger]

Just looked at 0.9.38. Strictly speaking they are useless because they are used for some RateData? that is used nowhere. Meanwhile found many, many places where clock().now() is (in-)directly called for RateData? that gets never used. And even most of the required ones are only used for display on the stats page.

[zzz]

In ab1409db90cb6889a2df8f52c85ad529ddc3ba5c to be 0.9.38-7