Loïc Sharma
ad7865d372
Revert "Listen to window notifications to update application lifecycle" (flutter/engine#44275)
Reverts flutter/engine#43558
Customer reported a crash on shutdown:
```
flutter::Window::HandleMessage(unsigned int,unsigned __int64,__int64)
...
?NtUserDestroyWindow
flutter::Window::Destroy()
flutter::Window::~Window()
flutter::FlutterWindow::`vector deleting destructor'`adjustor{312}' (unsigned int)
flutter::FlutterWindowsView::~FlutterWindowsView()
flutter::FlutterWindowsView::~FlutterWindowsView
FlutterDesktopViewControllerDestroy
flutter::FlutterViewController::~FlutterViewController
FlutterWindow::~FlutterWindow()
wWinMain
```
The message causing the crash is `WM_KILLFOCUS`.