devices/video/decoder: fix drain+clear queue issue
devices/video/decoder: fix drain+clear queue issue

Drain is cancelled by clearing either of the stream's queues. To work
around a limitation in the VDA api, the output queue is cleared
synchronously without going through VDA. Because of this, a drain
cancellation response from VDA might fail to find the drain's
AsyncCmdTag.

BUG=b:170184723
TEST=android.mediastress.cts.MediaRecorderStressTest#testStressRecordVideoAndPlayback

Change-Id: I1d54c9c4acfa7578addb947e1196313010a8431d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2535964
Reviewed-by: Chih-Yu Huang <f815e8cb2f117b8947610323682cb280404b8de3@chromium.org>
Reviewed-by: Alexandre Courbot <301cd6a3ea50a894b4b51e385c5eb12b9a4ffc0c@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Commit-Queue: David Stevens <2f87ba95ff5d327328bd68c2e86a4d9f2ba99bd0@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm