add DoS_tests.cpp
add DoS_tests.cpp

OpenNetworking/gcoin-community,l1204366/gcoin-community,l1204366/gcoin-community,l1204366/gcoin-community,l1204366/gcoin-community,OpenNetworking/gcoin-community,OpenNetworking/gcoin-community,OpenNetworking/gcoin-community,l1204366/gcoin-community,OpenNetworking/gcoin-community,l1204366/gcoin-community,OpenNetworking/gcoin-community,OpenNetworking/gcoin-community