Move x86_64-specific audit tests to sysdeps/x86_64/

[Roland McGrath]

I think most or all of those tests should be done on x86-32 too, perhaps
with some modifications.  Someone should at least file a bug about making
them run there.  Your change is fine as is, but given the future
applicability it might make sense to put the files in sysdeps/x86/ now
rather than move them again later (either way is fine with me).


Thanks,
Roland