lisp/frameset.el: Separate frame reusing from cleaning up.

lisp/frameset.el: Separate frame reusing from cleaning up.

* lisp/desktop.el (desktop-restore-forces-onscreen)
  (desktop-restore-reuses-frames): Use non-keyword values.
  (desktop-restore-frameset): Use CLEANUP-FRAMES arg of frameset-restore.

* lisp/frameset.el: Separate options for reusing frames and cleaning up.
  (frameset--reuse-list): Remove definition; declare.
  (frameset--action-map): Declare.
  (frameset--find-frame-if): Doc fix.
  (frameset--restore-frame): Cache frame action.
  (frameset-restore): New keyword arg CLEANUP-FRAMES, allows to select
  how to clean up the frame list after restoring.  Remove cleaning
  options from REUSE-FRAMES.  Change all keyword values to symbols.
  (frameset--jump-to-register): Simplify by using CLEANUP-FRAMES.