tests/migration-tests: Drop most WIN32 ifdefs for postcopy failure tests Most of them are not needed, we can stick with one ifdef inside postcopy_recover_fail() so as to cover the scm right tricks only. The tests won't run on windows anyway due to has_uffd always false. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de>