It is part of the generic_host_data_source_unittest.cc, able to be
implemented for other HDS as well. It executes INSERT statements and
a certain SELECT statement which Cassandra struggles in performance
with since it has to do two queries instead of a join. All statement
executions are timed and repeated on an increasingly number of hosts.
It is placed last and DISABLED_ as you don't want to run this during
a usual make check.