Don't set WM_TOPMOST on Windows.

This sometimes breaks toggling ALLEGRO_FULLSCREEN_WINDOW with OpenGL.

It doesn't appear to do anything, and we don't appear to set it in the
first place when the window is first created as
ALLEGRO_FULLSCREEN_WINDOW.

src/win/wwindow.c

@@ -868,10 +868,6 @@ static LRESULT CALLBACK window_callback(HWND hWnd, UINT message,
  d->flags &= ~ALLEGRO_MINIMIZED;
 
  if (LOWORD(wParam) != WA_INACTIVE) {
- // Make fullscreen windows TOPMOST again
- if (d->flags & ALLEGRO_FULLSCREEN_WINDOW) {
- SetWindowPos(win_display->window, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
- }
  if (d->vt->switch_in)
  d->vt->switch_in(d);
  _al_win_fix_modifiers();
@@ -888,11 +884,6 @@ static LRESULT CALLBACK window_callback(HWND hWnd, UINT message,
  return 0;
  }
  else {
- // Remove TOPMOST flag from fullscreen windows so we can alt-tab. Also must raise the new activated window
- if (d->flags & ALLEGRO_FULLSCREEN_WINDOW) {
- SetWindowPos(win_display->window, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
- SetWindowPos(GetForegroundWindow(), HWND_TOP, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
- }
  if (d->flags & ALLEGRO_FULLSCREEN) {
  d->vt->switch_out(d);
  }
@@ -1342,18 +1333,15 @@ bool _al_win_set_display_flag(ALLEGRO_DISPLAY *display, int flag, bool onoff)
  al_resize_display(display, display->w, display->h);
 
  if (onoff) {
- // Re-set the TOPMOST flag and move to position
- SetWindowPos(win_display->window, HWND_TOPMOST, mi.x1, mi.y1, 0, 0, SWP_NOSIZE);
+ // Move to position
+ SetWindowPos(win_display->window, HWND_TOP, mi.x1, mi.y1, 0, 0, SWP_NOSIZE);
  }
  else {
  int pos_x = 0;
  int pos_y = 0;
  WINDOWINFO wi;
  int bw, bh;
 
- // Unset the topmost flag
- SetWindowPos(win_display->window, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
-
  // Center the window
  _al_win_get_window_center(win_display, display->w, display->h, &pos_x, &pos_y);
  GetWindowInfo(win_display->window, &wi);