Move ns-win.el's rather wacky menu adjustments to menu-bar.el.

Move ns-win.el's rather wacky menu adjustments to menu-bar.el.

* lisp/term/ns-win.el: Do not require easymenu.
(menu-bar-edit-menu) <copy, paste, paste-from-menu, separator-undo>:
<spell>: Move adjustments to menu-bar.el.
* lisp/menu-bar.el (menu-bar-edit-menu) <copy, paste, paste-from-menu>:
<separator-undo, spell>: Move ns-win's adjustments here.
* lisp/loadup.el [ns]: Do not load easymenu.

* src/Makefile.in (SOME_MACHINE_LISP): Remove easymenu.elc.
* lib-src/makefile.w32-in (OTHER_PLATFORM_SUPPORT): Remove easymenu.elc.