ofproto-dpif-xlate: Limit memory and time that translation can consume.

The resubmit depth has been limited to MAX_RESUBMIT_RECURSION, currently
64, for a long time.  But the flow "actions=resubmit:1, resubmit:2,
output:1" generates about 2**MAX_RESUBMIT_RECURSION output actions,
exhausting memory.  This commit fixes the problem.

Such a flow also requires 2**MAX_RESUBMIT_RECURSION time for translation.
This commit fixes that problem too.

Bug #19277.
Reported-by: Paul Ingram <paul@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Justin Pettit <jpettit@nicira.com>