max_dynamic_hosts in TCPPING

@Property(description="max number of hosts to keep beyond the ones in initial_hosts")
protected int max_dynamic_hosts=100;
protected final BoundedList<PhysicalAddress> dynamic_hosts=new BoundedList<PhysicalAddress>(max_dynamic_hosts);
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Even though set the max_dynamic_hosts with xml config, dynamic_hosts would still init before max_dynamic_hosts be covered