WL#986: Check if new hash function gives better results

There is a hash function which Oracle and PostgreSQL uses, referenced here:
http://burtleburtle.net/bob/c/lookup.c 

We shall check if this function is better then the one we currently use
(located in) mysys/hash.c

The criteria for hash function goodness should not only hash generation speed,
but also even distribution values on given range for different types and
distribution of base data.