message: Fix fuzzer-found bug in fuzzer
  The fuzzer itself does not call the APM API correctly.
  Cr-Commit-Position: refs/heads/master@{#29922}
diff: @@ -122,8 +122,8 @@ void FuzzAudioProcessing(test::FuzzDataHelper* fuzz_data,
  StreamConfig(output_rate, num_channels), ptr_to_float_frames);
  } else {
  apm_return_code = apm->ProcessReverseStream(
  - ptr_to_float_frames, StreamConfig(input_rate, 1),
  - StreamConfig(output_rate, 1), ptr_to_float_frames);
  + ptr_to_float_frames, StreamConfig(input_rate, num_channels),
  + StreamConfig(output_rate, num_channels), ptr_to_float_frames);
  }
  } else {
  const int num_channels = fuzz_data->ReadOrDefaultValue(true) ? 2 : 1;
  