Fix style warnings.
* Reorder the CAS macro helper routines. The macro and its functions are
defined only in make-host-2, so when you give the lambdas to the host,
it might ("will", if self-hosted) compile them and warn about as-yet-unknown
functions, since as far it knows, there is no surrounding compilation unit.
* For things aren't needed until startup, while they could be rearranged
in the above manner, skip the :compile-toplevel situation.
* DEFINE-ASSEMBLY-ROUTINE is called by both make-host passes,
but mentions functions that are not even eventually seen in make-host-2,
so skip the :load-toplevel situation.