tests: qemumonitorjson: Do some useful testing in the 'simple' tests
tests: qemumonitorjson: Do some useful testing in the 'simple' tests

The 'simple' monitor tests were quite useless, since the code did not
even check whether the correct command was called.

This patch uses the QAPI schema validator to validate that the arguments
are in format according to the schema.

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

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