WL#3682: Select proper TC from MySQL Server

In order to scale benchmarks and applications using more than 1 nodegroup
it is essential that selection of TC is handled in an optimised manner from
MySQL Server.

The idea to handle this is that the first transaction if it accesses only
one partition then the primary node of that partition will be selected
for TC.

This work will be performed most likely in NDB handler.

This will make execution of DBT2 on very large scale possible and also
many other benchmarks and applications. It's likely that this will cause
a speed-up of a factor of 3-4 for large clusters when running DBT2.

It is also essential to support the establishment of a new business area
for MySQL Cluster for real-time applications such as financial applications
for trading.