MULE-7731 JMS transport should reuse javax.jms.Session, javax.jms.Messag...

...eProducer instances by default
I don't see how reusing Session/Producer will change the user behaviuor when both of these objects are designed to be resused, do you have an example or how behaviuor would change?  We should have always reused these objects in Mule, it is an anti-pattern to request a Session/Producer from the ConnectionFactory for every request.

JMS ConnectionFactories provided in in ApplicationServers via a JCA interface often have functioanlity for caching session, but AFAIK standard connectionFactories for standalone use generaly do not (i checked WMQ/ActiveMQ).  That said, even if a connectionFactory that does support caching is used, this wouldn't present a problem.