Fix bug in recent transformations that caused inadvertent shadowing.

Fix bug in recent transformations that caused inadvertent shadowing.

The real fix is to make cgen do alphatization, in which case copy.scm
could be considerably simplified, but this hack works for now to fix,
e.g., miscompilation of INITIALIZE-PACKAGE! in runtime/emacs.scm,
which has

(let ((type (select-console-port-type)))
  (if (let ((type (port/type the-console-port)))
        (or (eq? type vanilla-console-port-type)
            (eq? type emacs-console-port-type)))
      (set-port/type! the-console-port type)))

=>

(let ((type (select-console-port-type)))
  (let ((type (port/type the-console-port)))
    (if (or (eq? type vanilla-console-port-type)
            (eq? type emacs-console-port-type))
        (set-port/type! the-console-port type))))

One of the variables formerly named TYPE is now named by an uninterned
symbol instead.