tests: refactor qemuMonitorTestProcessCommandDefaultValidate
tests: refactor qemuMonitorTestProcessCommandDefaultValidate

Use VIR_AUTO* for cleanup and virBufferCurrentContent instead
of virBufferContentAndReset.

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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