Destroy output tracks when existing.

Bug: 364404031
Test: manually
Flag: EXEMPT bugfix
Change-Id: I4e83ee6d7cca38c62448ccb3019a7d2275cc664e
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 76e4712..1c8d98a 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -7851,6 +7851,9 @@
         audio_utils::lock_guard l(mutex());
         localTracks = std::move(mOutputTracks);
         mOutputTracks.clear();
+        for (size_t i = 0; i < localTracks.size(); ++i) {
+            localTracks[i]->destroy();
+        }
     }
     localTracks.clear();
     outputTracks.clear();