Nicholas Irving (nirving@darkedges.com)

* Fixed an issue where the ClassLoader was being hit heavily to check to see what Spring Dialect was being used. Now check from one class instead of the ClassLoader. This improves a lock found in WebLogic 10.3.6, even after using a Filtered ClassLoader.

Instead of checking if what classes are on the ClassPath everytime with Class.forName, this change caches the class lookup for each Spring Dialect. I have seen similair changes in the code base to cache configuration items, but not the class. This improveda lock found in WebLogic when executing over 20+ requests per second.