unittest: recycle packet before exit

To avoid an issue with flow validation, we need to recycle the packet
before cleaning the flow.
unittests: some functions needs a flow lock.

In debug validation mode, it is required to call application layer
parsing and other functions with a lock on flow. This patch updates
the code to do so.
unittests: fix stream-tcp.c

Lock and recycle fixes for stream-tcp.c
IsRuleReloadSet() shouldn't return an uninitialized value