xen/livepatch: fix livepatch tests

xen/livepatch: fix livepatch tests

The current set of in-tree livepatch tests in xen/test/livepatch started
failing after the constify of the payload funcs array, and the movement of the
status data into a separate array.

Fix the tests so they respect the constness of the funcs array and also make
use of the new location of the per-func state data.

Fixes: 82182ad7b46e ('livepatch: do not use .livepatch.funcs section to store internal state')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>