Fix #4352: elliptic_e(1,1.23) signals lisp error on complex number

Fix #4352:  elliptic_e(1,1.23) signals lisp error on complex number

`elliptic_e` calls `elliptic-e` to evaluate `elliptic_e(1,1.23)`.
This calls `elliptic-ec` which returns a Maxima complex number because
it calls `to` before returning.  That's not right; it should just
return a Lisp complex number and the caller needs to handle that
appropriately.