Make sure we don't use objects by ref in setMwGlobals

If we copy am object by ref into our temporary array
then this doesn't really make this method very useful
as the same object would be restored, with any changes
after the test has run.

Thus objects should be cloned when being dumped in
here, we use unserialize() and serialize() instead as
we would also want to clone the objects within the
object to avoid changes in there!

These is no point in adding an if is_object call so
we just serialize and deserialize everything!

Change-Id: I5e4ef114405888932014edae6b44afc6ee2c4863