Fix for issue matplotlib#17769

1) On figure window (FigureFrameWx) close - remove figure manager from from Gcf class
 previously Gcf.destroy was called with FigureFrameWx not FigureManagerWx instance so figure was not removed.
2) Destroy now done from FigureManagerWx.destroy() method to prevent multiple calls to the close event handler.
3) Remove unneeded wx mainloop yield calls that cause crash on windows form both FigureManagerWx.destroy and FigureFrameWx.Destroy

lib/matplotlib/backends/backend_wx.py

@@ -971,9 +971,7 @@ def _onClose(self, event):
         _log.debug("%s - onClose()", type(self))
         self.canvas.close_event()
         self.canvas.stop_event_loop()
-        Gcf.destroy(self)
-        if self:
-            self.Destroy()
+        Gcf.destroy(self.figmgr)
 
     def GetToolBar(self):
         """Override wxFrame::GetToolBar as we don't have managed toolbar"""
@@ -992,9 +990,6 @@ def Destroy(self, *args, **kwargs):
             super().Destroy(*args, **kwargs)
             if self.toolbar is not None:
                 self.toolbar.Destroy()
-            wxapp = wx.GetApp()
-            if wxapp:
-                wxapp.Yield()
         return True
 
 
@@ -1043,10 +1038,7 @@ def destroy(self, *args):
         _log.debug("%s - destroy()", type(self))
         frame = self.frame
         if frame:  # Else, may have been already deleted, e.g. when closing.
-            frame.Close()
-        wxapp = wx.GetApp()
-        if wxapp:
-            wxapp.Yield()
+            frame.Destroy()
 
     def full_screen_toggle(self):
         # docstring inherited