Release buffers on MediaCodec#stop()

Release all buffers on Codec2 stop() in order to quick release in case
of using multiple Codec's from application.

Bug: 146679370
Test: atest CtsMediaTestCases -- --module-arg CtsMediaTestCases:size:small
Change-Id: I7a025c2d349442f93dbfab0bd1892df46229ef56
diff --git a/media/codec2/sfplugin/CCodec.cpp b/media/codec2/sfplugin/CCodec.cpp
index 01d106f..1e4560c 100644
--- a/media/codec2/sfplugin/CCodec.cpp
+++ b/media/codec2/sfplugin/CCodec.cpp
@@ -1406,6 +1406,9 @@
         // TODO: convert err into status_t
         mCallback->onError(UNKNOWN_ERROR, ACTION_CODE_FATAL);
     }
+    // Assure buffers are not owned when stop() was called without flush().
+    std::list<std::unique_ptr<C2Work>> flushedWork;
+    mChannel->flush(flushedWork);
 
     {
         Mutexed<std::unique_ptr<Config>>::Locked configLocked(mConfig);