wasapi: Add NULL checks to avoid crashing during media playback if the audio device removed.  From BMO #1199794.
wasapi: Add NULL checks to avoid crashing during media playback if the audio device removed.  From BMO #1199794.

kinetiknz/cubeb,padenot/cubeb,kinetiknz/cubeb,kinetiknz/cubeb,padenot/cubeb,padenot/cubeb,ieei/cubeb,ieei/cubeb