Main reason for this was there was a crash in shutdown of the server
in binlog_encryption.encryption_combo-mix and some other tests because
something in listen_sockets where not initialized. Changing to
Dynamic_array caused things to work.
Other reason for removing std::vector was that it is harder to debug,
and not integrated with DBUG, safemalloc, valgrind or memory
calculation and cause code explosions (extra code generated for each
std::vector type used).