src/parser/scanner-proto.lisp: Reorder declarations.

src/parser/scanner-proto.lisp: Reorder declarations.

The `token-scanner' and `token-scanner-place' objects refer to each
other recursively through their slot types.  SBCL's loader objects to
this if `token-scanner-place' -- a structure type -- is first.  Reorder
them so that `token-scanner' -- a CLOS class -- is first, because that
seems to work better.