AudioFlinger: do not enter standby on offload stream when underrunning

When an offloaded track has been underrunning long enough for the
stream to enter standby, do not enter standby: entering standby will
release DSP resources and cause problems if we resume after recovering
from the underrun.

Bug: 322874013
Fixes: 333970720
Test: offload playback test with forced underrrun
Change-Id: I942fd3f401c226977f4f0684ed0e5a7a03db735d
diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index 6c22e21..89ee5c0 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -275,6 +275,8 @@
     void triggerEvents(AudioSystem::sync_event_t type) final;
     void invalidate() final;
     void disable() final;
+    bool isDisabled() const final;
+
     int& fastIndex() final { return mFastIndex; }
     bool isPlaybackRestricted() const final {
         // The monitor is only created for tracks that can be silenced.