EVS memory increase with FIX_264_AUDIO_CHANNELS_TO_HEAP

After the introduction of FIX_264_AUDIO_CHANNELS_TO_HEAP, the RAM increased significantly for EVS / StereoDmxEVS (see https://ivas-codec-pc.3gpp.org/ivas-codec/complexity-StereoDmxEVS-stereo-in-mono-out-public/index.html) which was not expected.