Correct mouse handling when window origin changes between down and up events

Correct mouse handling when window origin changes between down and up events

Do this by using frame relative positions rather than window relative ones,
which gave rise to spurious drag events when the origin of the window changed
between the mouse down and up events.  This fixes bug #48409.

* keyboard.c (frame_relative_event_pos): New static variable.
(make_lispy_event): Record frame relative position of down event.  When the up
event is in the same position, "move" this event into the window of the down
event when this window (typically a mini-window) is no longer under the mouse.
Call make_lispy_position a second time to generate this changed event.
(syms_of_keyboard): Declare Qwindow_edges.  static_pro
frame_relative_event_pos.