svga: Fix out-of-sync backing surface

svga: Fix out-of-sync backing surface

When a backing surface is reused, it is possible that
the original surface has been changed. So before the backing surface
is bound again, we need to sync up the surface.
This patch creates a new helper function svga_texture_copy_handle_resource()
to sync up the backing surface resource.

This patch, together with the backing surface dirty bit fix, fixes
the rendering corruption in NobelClinicianViewer when rotating the model.

Also tested with MTT glretrace, piglit, Cinebench, Turbine.

Reviewed-by: Brian Paul <brianp@vmware.com>