tests: qemuxml2argv: Add infrastructure for testing with real qemuCaps
tests: qemuxml2argv: Add infrastructure for testing with real qemuCaps

Allow testing of XML->argv conversion with using a real capability map
as used in the qemucapabilitiestest. This allows specifying the required
qemu version with the test rather than having to enumerate all the
required capabilities or allows to use the newest capabilities present.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>

jardasgit/libvirt,jardasgit/libvirt,jfehlig/libvirt,crobinso/libvirt,nertpinx/libvirt,libvirt/libvirt,eskultety/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,libvirt/libvirt,zippy2/libvirt,jfehlig/libvirt,olafhering/libvirt,fabianfreyer/libvirt,zippy2/libvirt,olafhering/libvirt,andreabolognani/libvirt,crobinso/libvirt,jfehlig/libvirt,zippy2/libvirt,nertpinx/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,eskultety/libvirt,crobinso/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,zippy2/libvirt,olafhering/libvirt,crobinso/libvirt,jardasgit/libvirt,jardasgit/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,libvirt/libvirt,fabianfreyer/libvirt,libvirt/libvirt,fabianfreyer/libvirt,eskultety/libvirt,nertpinx/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt