Fix bug #14032 with restoring frame dimensions on MS-Windows.

Fix bug #14032 with restoring frame dimensions on MS-Windows.

 src/w32term.c (w32fullscreen_hook): Record last value of the frame's
 'fullscreen' parameter.  Always record previous width and height
 of the frame, except when switching out of maximized modes, so
 that they could be restored correctly, instead of resetting to the
 default frame dimensions.  Send SC_RESTORE command to the frame,
 unless we are going to send SC_MAXIMIZE, to restore the frame
 resize hints in the mouse pointer shown by the window manager.
 src/frame.c (get_frame_param): Now extern for WINDOWSNT as well.
 src/lisp.h (get_frame_param): Adjust conditions for prototype
 declaration.