TEIIDDES-879: Actually make use of the jar in the connection JAR_LIST

* The connection class was modified to fetch the teiid driver using the
  roundabout route of finding the client runtime plugin supported by the
  version specified then loading its driver.

* However, the classloader provided is created from the jar list defined
  in the DTP driver instance configuration and as such should already
  contain the most appropriate driver, especially as the list is now
  auto-created by default.

* Use the driver from the classloader first and only if that fails resort
  to the more circuitous route of obtaining a driver.