OPENJPA-2668 fix for query execution leaking into CriteriaQuery

[michaelwiles]

for OPENJPA-2668 added copy method to Expressons.In and use that to return the expression so that the original is not changed.

Not sure if there's a better way to do this. This is quite how can I say, simple?

This is the only Expression that I could find that dirties the original CriteriaQuery and I'm fairly convinced that this shouldn't happen.

Prior to this fix, executing the test would change the query and replace the parameter with the hydrated parameter values.