tests: Test IOThread related functions for test driver
tests: Test IOThread related functions for test driver

testIOThreadAdd tests iothreadinfo and iothreadadd
testIOThreadDel tests iothreadinfo and iothreaddel
testIOThreadSet tests domstats and iothreadset
testIOThreadPin tests iothreadadd, iothreadinfo and iothreadpin

Above tests should cover the IOThreads related APIs for test driver

Signed-off-by: Luke Yue <52cb389a9dce6ad23a1ccbef87c68e8ebf30699c@gmail.com>
Reviewed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

zippy2/libvirt,crobinso/libvirt,nertpinx/libvirt,crobinso/libvirt,olafhering/libvirt,libvirt/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,nertpinx/libvirt,nertpinx/libvirt,nertpinx/libvirt,zippy2/libvirt,jfehlig/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,libvirt/libvirt,nertpinx/libvirt,jfehlig/libvirt,crobinso/libvirt,olafhering/libvirt,jfehlig/libvirt,olafhering/libvirt,zippy2/libvirt