qemuhotplugtest: Add tests for ccw devices

qemuhotplugtest: Add tests for ccw devices

There's a plan to rework the address handling, so testcases
that verify hotplugging ccw devices will help in avoiding
regression.

In this commit, some files are duplicated because of the way
qemuhotplug.c calculates the expected xml filenames.
I plan on changing that to explicitly stating the basis domain
xml, the device xml, and the expected xml.