Clean up references to AUDIO_FORMAT_PCM_8_24_BIT

Change-Id: I08771eb2664b7082561a40937218c7f4414e2cce
diff --git a/media/libeffects/testlibs/AudioFormatAdapter.h b/media/libeffects/testlibs/AudioFormatAdapter.h
index 41f1810..dea2734 100644
--- a/media/libeffects/testlibs/AudioFormatAdapter.h
+++ b/media/libeffects/testlibs/AudioFormatAdapter.h
@@ -75,6 +75,7 @@
         while (numSamples > 0) {
             uint32_t numSamplesIter = min(numSamples, mMaxSamplesPerCall);
             uint32_t nSamplesChannels = numSamplesIter * mNumChannels;
+            // This branch of "if" is untested
             if (mPcmFormat == AUDIO_FORMAT_PCM_8_24_BIT) {
                 if (mBehavior == EFFECT_BUFFER_ACCESS_WRITE) {
                     mpProcessor->process(