Do not invalidate stream when the secondary outputs are changed.

When a dynamic policy is registered, the secondary outputs may be
changed. Instead of tearing down the tracks, only tracks whose secondary
outputs are changed will be updated with the new secondary outputs.

Bug: 181582467
Bug: 174123397
Test: atest AudioPlaybackCaptureTest audiopolicy_tests
Test: repo steps in the bug
Change-Id: I9a47a0a4b37ad3f4a1d554dd726ebffb27325141
(cherry picked from commit 10a03f1713e29eadfa862087e504f9e14964387e)
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 17acb16..d4fb995 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -1013,6 +1013,8 @@
                     mDownStreamPatch = *patch;
                 }
 
+                PlaybackThread::Track* getTrackById_l(audio_port_handle_t trackId);
+
 protected:
     // updated by readOutputParameters_l()
     size_t                          mNormalFrameCount;  // normal mixer and effects