Upgrade the openebs/tests-tpcc-client container to perform parallel database load in tpcc-runner.sh

[ksatchit]

The openebs/tests-tpcc-client container currently performs the following step to load the database with entries (as per the number of warehouses specified in the tpcc.conf benchmark config file) before running the actual benchmark test (tpcc_start) :-

./tpcc_load -h <DB_SERVER_IP> -P3306 -d<DB_NAME> -u <DB_USER> -p <DB_PASSWORD> -w

This is a sequential process that increases in duration with the number of warehouses specified, thereby delaying the start of the actual benchmark.

This process can be made quicker by running multiple parallel tpcc_load operations on a subset of warehouses. There is already a script (load.sh) provided by percona in the tpcc-mysql repo which does this - we need to use it in the tpcc-runner.sh with the logic to identify completion of all tpcc_load processes before proceeding to start the benchmark

[ksatchit]

Moved issue to openebs/test-tools repo: litmuschaos/test-tools#19