Re: [PATCH v4 0/6] MR9453: xactengine3/tests: Add many more tests.

[Elizabeth Figura (＠zfigura)]

This comes from IAudioClient::GetMixFormat() returning AUDCLNT_E_DEVICE_IN_USE, probably because alsa_open_device() is getting EBUSY from snd_pcm_open(). FAudio, typically, has zero error handling, and just blithely tries to dereference the format it receives. This isn't really something I can address in the test, but I'll submit a fix to faudio.