Swap buffers fails on application exit when Animator is running

Run the attached QML code as a Wayland client. It will terminate after 1s and print a warning:

qt.qpa.wayland: eglSwapBuffers failed with 0x300d, surface: 0x0

Error code 0x300d is EGL_BAD_SURFACE (since surface is null). That's a regression to 6.5.6 (and seems to occur on no other platform, except Wayland).