Change batch finalization timeout mechanism from

Handler#sendMessageDelayed() to a wakeful alarm

Messages sent with Handler#sendMessageDelayed() didn't get delivered
until the device woke up after being idle, which resulted in
potentially very long windows of logs accumulation and highly possible
network log loss from before the device becaming idle.

Bug: 34157435
Test: manual with decreased timeout over a few timeout iterations
Change-Id: I50b29b9f132856a629e28f46c022f21976bd92fb