We change memtable size from 200MB to 100MB to achieve smoother flush performance. We change loadStreamPerNode from 20 to 60 to avoid stream rpc to be the bottleneck when enable memtable_on_sink_node. We change default s3&broker load parallelsim to make the most of CPUs on moderm multi-core systems. Signed-off-by: freemandealer <freeman.zhang1992@gmail.com>