For selected window have (set-)window-point always operate on buffer's point.
* window.c (Fwindow_point): For the selected window always return
the position of its buffer's point.
(Fset_window_point): For the selected window always go in its
buffer to the specified position.
* window.el (window-point-1, set-window-point-1): Remove.
(window-in-direction, record-window-buffer)
(set-window-buffer-start-and-point, split-window-below)
(window--state-get-1, display-buffer-record-window): Replace
calls to window-point-1 and set-window-point-1 by calls to
window-point and set-window-point respectively.